L13: Laser Therapy Flashcards
What is the safety precaution with Laser?
Possible damage to the eyes
What does LASER stand for?
Light
Amplification by the
Stimulated
Emission of
Radiation
A laser generates a beam of ______ waves within the _____, ____ or ____range of the electromagnetic spectrum (wavelengths 100nm‐1mm)
electromagnetic; infrared (IR), visible or UV
What are 3 main characteristics of how laser radiation differs from ordinary lights?
- Monochromaticity
- Coherence
- Collimation
What are 2 characteristics of monochromaticity in laser radiation?
- Single specific frequency
- Defined wavelength eg ruby lasers give a red light at 694.3nm
What are 2 characteristics of coherence in laser radiation?
- Temporal – in phases, peaks and troughs all at same time
- Spatial – all travelling in same direction
What are 3 characteristics of collimation in laser radiation ?
- Remain in a parallel beam (Can focus it very well)
- Does not diverge from point source
- Can be used for measurement over long distances
What are the 3 types of light?
- White light
- Laser light
- LED light
What are 2 characteristics of white light?
- Multiple wavelengths
- Non coherent
What are 2 characteristics of laser light?
- Single wavelength
- Coherent
What are 2 characteristics of LED light?
- Monochromatic
- Non‐coherent
What are 3 properties of laser?
- Reflection (Eg. don’t want to shine in the mirror)
- Refraction ‐ Focussed or Scattered
- Absorption
- Penetration Depth of red light = 1‐2 mm
- Penetration Depth of infrared = 2‐4 mm
Does laser get absorbed deeply or more superficial?
Not very deeply absorbed
There are ____ and ____ effects in medicine (Class ____ lasers)
Photothermal; photoablative; 4
What lasers are used for physiotherapy?
non‐thermal –> low level laser therapy (LLLT)
Physiotherapists use Class 2, 3A or 3B lasers
What 3 classes of laser that physiotherapists use?
Class 2, 3A or 3B lasers
What is the advantage of using LLLT (Low level laser therapy)?
Fairly small devices that is able to be moved around
What are the 4 types of laser?
Laser production is most commonly mains supply “_____” the lasing medium
pumps
What are 2 lasing medium?
- Gas
- Semi‐conductor (diode lasers)
For lasing mediums, these media when “pumped” by the power source emit a ____ of _____ due to a stimulated quantum jump from higher to lower energy state of the electrons
large number; identical photons
What are 5 characteristics of resonating cavity?
- Cavity of chamber containing lasing medium
- Pair of parallel reflecting mirrors
- Photons of light reflected back and forth
- One of the mirrors is not “pure”
- Allows some of the light to emit out
What do laser probes look like?
What is energy density?
Amount of energy falling on a surface measured in J/cm‐2
What is rate at which energy is produced by laser measured in?
joules/cm‐2 per second ie Watts
1 Watt = 1 J/cm2
What is power density?
the amount of energy they produce per second per unit area
How are lasers classified?
Power density- the amount of energy they produce per second per unit area
Therapeutic lasers used by physios usually in ____
mW
What are the 2 types of pulsed laser?
temporal peak power or temporal average power
How long should you use a therapeutic laser for?
20-30 secs for each point (similar to ERAs in ultrasound)
What are the 4 classification of laser?
What is the power in a class 1 laser?
Low
What is the power in a class 2 laser?
Low up to 1mW
What is the power in a class 13Alaser?
Low-medium up to 5mW
What is the power in a class 3B laser?
Medium up to 500mW
What is the power in a class 4 & 5 laser?
High over 500 mW
What are the effects in a class 1 laser?
None on eyes or skin