LASER Flashcards
Light Amplification by Stimulated Emission of Radiation
Photon that hits atom that is already excited
This creates radiation effect
History of LASER: 1917
1917 Einstein - concept of stimulated emission of radiation
Biophysical father of LASER
Albert Einstein
History of LASER: 1954
Shawlow, Townes, Basoc and Prochorov
MASER
1st stimulated emission device
History of LASER: 1960`
Javan and Maiman
Ruby LASER - maiman
He-Ne LASER - javan
Visible portion of em spectrum
History of LASER: 1962
White et al
Cold LASER
Indigoviolet portion of roygbiv of light
History of LASER: 1960-1970
endre mester Low level LASER diode type Non thermal effects of LASER Therapeutic father of LLLT Was only used by doctors
History of LASER: 2002
low intensity laser in rehabilitation
On EM spectrum, it is close to —- and ——
infrared and visible
properties of laser
Monochromatic : single frequency and wavelength making one color
Coherent : moves in one direction
Collimated : multiple wavelengths of radiation move parallel to each other
LASER produces —- intensity light in —- area/s
high, one
LASER physical components (gaseous and photodiode)
active medium (lasing agent); helium-neon; gallium arsenide, gallium-aluminum arsenide;
resonance chamber; sealed glass cylinder; diode p=n junction gap
power source; electrical; electrical
spontaneous emission
Absorption: When you plug the machine, the electrons move to higher energy shells
Emission: moves inwards to lower energy shell, creates radiation
Made of various wavelengths, therefore not monochromatic
stimulated emission is made of — wavelengths, therefore you make a —–
Made of similar wavelengths, therefore you make a laser
longer wavelength = —- frequency = —— penetration
lower frequency, deeper penetration
red light vs violet light
violet = shorter wavelength
red = longer wavelength
red light penetration
600-700 nm
Helium-neon LASER penetration
632.8 nm
Ruby LASER penetration
694.3 nm
gallium aluminum arsenide LASER penetration
860-780 nm
gallium arsenide laser penetration
904-910 nm
power (mW)
rate of energy flow
power density (mW/cm2)
amount of power per unit area
maximum of 100 mW/cm2
class 1
power: <0.5 mW
no hazard
class 1M
power: <0.5 mW
no hazard because of large diameter beam or less-divergent beam
class 2
power: < 1 mW
safe for momentary viewing
provokes blink reflex
class 3A
<5 mW
Laser pointers; eye hazard with prolonged exposure
class 3B
<500 mW
for therapy; permanent eye damage with brief exposure, viewing of siffused beam reflected from skin is safe; minor burns with long exposure
class 4
> 500 mW
surgical and industrial cutting laser
permanent eye damage
serious skin burns
burns clothing
photobiomodulation
light modulates biological processes
enhances cellular function
energy=
power x time
energy density
energy / area of irradiation
therapeutic range of energy density
0.5 to 20 j/cm2
process of photobiomodulation
light => chromophore activation => mitochondrial cytochrome oxidative metabolism => photobiomodulation => analgesia, alter NCV, anti-inflammation, inc. collagen and protein synthesis, enhanced cell metabolism (ATP & RNA)
indications of laser
pain control, inflammation control, wound healing
wounds, tendinopathies, trigger points, RA, OA, TMJ, carpal tunnel
first laser for inhibiting bacterial growth of P. aeruginosa and S. aureus
red laser (632.8 or 670 nm)
Laser for inhibiting bacterial growth of P. aeruginosa, S. aureus & e. coli
HeNe Laser (630 nm) at 1-20 J/cm2
another laser for inhibiting bacterial growth of P. aeruginosa and S. aureus
blue light (405 nm) at 10-20 j/cm2
laser for vasodilation
red Laser
contraindications
Over eyes Malignancy Within 4-6 months of radiotherapy Hemorrhage Over the thyroid Low back/abdomen of pregnant patient Epilepsy Pacemakers (for clinics)
precaution
Metal implants Epiphyseal plates in children Impaired sensation Impaired mentation Photophobia (you can proceed with proper patient education)
energy density for soft tissue healing
5-16 j/cm2
energy density for fracture healing
5-16 j/cm2
energy density acute arthritis
2-4 j/cm2
energy density lymphedema
1-5 j/cm2
energy density neuropathy
10-12 j/cm2
energy density acute soft tissue inflammation
2-8 j/cm2
energy density chronic soft tissue inflammation
10-20 j/cm2
energy density chronic arthritis
4-8 j/cm2
techniques of application
Stationary with contact
Stationary with non-contact (open wounds and infection)
Gridding (point by point)
Scanning => Like ultrasound, For larger areas
documentation
May indicate specific type of LASER in very first part
LASER x power x energy density on body area to rationale
