Chapter 1: Introduction To Photothermolysis Flashcards
What does Laser stand for?
Light Amplification Stimulated Emission Radiation
What is laser light? (The electromagnetic spectrum of radiation)
Laser light is really a sophisticated method of converting light into energy for use as in devices with many applications in nearly every major industry
What is sunlight?
Sunlight is a beam or a ray of light that is made up of a variety of invisible and visible forms of electromagnetic energy
—commonly called EM energy
What is a wavelength?
It is measured from the distance from the top of one wave (amplitude) to the top of the next.
Visible Spectrum of Light:
Light is measured by its _____________ in _____.
Wavelength in nanometers.
What is the wavelength of violet light?
400nm-420nm
What is the wavelength of Indigo?
420nm-440nm
What is the wavelength of Blue?
440-490nm
What is the wavelength of green?
490nm-570nm
What is the wavelength of yellow?
570nm-585nm
What is the wavelength of orange?
585nm-620nm
What is the wavelength of red?
620nm-780nm
What is one wavelength equal to?
One wavelength equals the distance between two successive wave crests or troughs
What is Ionizing radiation (ionizing vs non-ionizing radiation)
- occurs at short wavelengths <400nm
- strips the elctrons from transport media
- alters cellular function
- causes mutation on DNA (ex: X-rays, ultraviolet UV rays)
Http://youtu.be/rApXQmkpk-Q
What is non-ionizing radiation? (Ionizing vs. Non-ionizing radiation)
- it can NOT strip electrons from transport media
- can NOT alter cellular function
- greatest risk is Ocular (eye) damage. (Ex: medical lasers, IPL machines)
Properties of laser light:
- lasers have unique properties that are not seen in any other type of energy form
- normal white light (flashlight or light bulb) is made of a multitude of visible and invisible infrared wavelengths merged and created white light that’s can quickly disperse in space within a short distance.
What are the 4 effects laser light can have on tissue of the skin (tissue effects)
- Absorption
- Reflection
- Transmission
- Scatter
What is photothermolysis (how do we use light energy?)
- the absorption of light by chromosphere’s (hemoglobin, melanin or water)
- the transformation of absorbed light into heat (thermo)
- the breakdown of cells (lysis)
What is a chromophore?
Melanin, Collagen, Hemolglobin, and water
Particles in our body which absorb light
What are the 5 parameters of photothermolysis?
- Wavelength
- Pulse width (pulse duration)
- Exposure time
- TRT: thermal relaxation time
- Fluence
What is a wavelength?
-the distance between two successive wave crests or troughs
What is Pulse width (pulse duration)?
-the amount of time the laser is emitted on the skin measured in nanosecond and millisecond.
What is Exposure Time?
-should be less than or equal to the time necessary for cooling of the target structure
What is TRT
- thermal relaxation time of a mass is the time required for it to cool down to the normal temp of the surrounding tissue
What is fluence?
-the energy delivered per unit area
What is the process of selective photothermolysis?
- The use of light energy to target a particle that’s is in our body which absorbs light.
- These particles are called chromophores
Chromophore facts: (2)
- there are many types of chromophores
- studies have mapped the wavelength absorption of each chromophore
Selective Photothermolysis is achieved by: (3)
- Wavelength
- Pulse width/ duration
Thus causing…
- Exposure Dose/ Joules
How is photothermolysis achieved through wavelength?
-selective absorption- the longer the wavelength, the deeper the penetration
How is photothermolysis achieved through pulse width/ duration?
- heat confinement
- pulse duration is measure in nanoseconds (ns) or milliseconds (ms) it is the timing of the light energy or how long the laser is actually on the skin
How is photothermolysis achieved with exposure dose/ joules?
-fluence refers to the energy of the pulsed laser beam it is expressed in joules per square centimetre (J/CM2) and refers to energy x time