Low level laser therapy Flashcards
What does LASER stand for?
light amplification by stimulated emmision of radiation
what theory is laser based on?
theory of albert einstein
what are the higher frequencies of light?
x rays, gamma rays, ultraviolet cause ionization
visible light
violet
infared
ultraviolet
light is transmitted as waves and is packaged in what?
photons
what are the principles of laser generation
adding energy to electrons causes them to move to higher orbit
if the electron gives up energy it moves to a lower orbit
spontaneous emission
what is spontaneous emission?
giving up energy
describe stimulated emissions
an excited atom will release a photon
if that photon interacts with another excited atom, it will release another photon
both photons have identical frequency, direction and phase
both photons continue to cause the release of other identical photons as long as excited atoms are present
population inversion
the number of excited atoms outweighs the number at ground state
pumping
the application of an external source of power to the lasing medium
causes population inversaion
what are the 5 ways to produce a laser?
pumping of active medium population inversion spontaneous emission stimulated emission amplification
coherence
same wavelength and all in phase
light is emitted in an organized fashion rather than randomly as in a light bulb
monochromatic
single color, same wavelength
collimation
photons move in a parallel fashion, they don’t diverse
wavelength
longer (lower frequency)= deeper penetration
name the types of lasers
gas
solid
semiconductor
liquid
types of gas, liquid and solid lasers
helium-neon gas in lasing chamber
semiconductor laser
tow layers of material in silicon matrix
layer inteface is reflective
what helps determine the depth of penetration?
melanin or hemoglobin increase, the depth of penetration of the light decreases
the wavelength of the light will determine the overall depth of penetration the photons will attain
application of laser
laser should be in light contact with patient
90 degree angle to the treatment area
cover each square centimeter of the treatment area
what is the alternate method of application?
scanning technique
hold laser 5-10m from skin
energy level decreases with distance
alter intensity to take that into account
photobiomodulation
effect is from absorption of photons of light by cells
photobiostimulation
lower doses of laser
photobioinhibition
higher doses of laser
chromophores
molecules which accpet energy from photons
cytochromes
cytochromes are located where?
in mitochrondria
sensitive to light photons
absorption of photons triggers biochemical reactions
cellular mechanisms of laser
changes in Na-K channel
increase intracellular calcium
the calcium flux affects the level of cyclic nucleotides, which modulate DNA and RNA synthesis, which modulates cell proliferation
biological effects of low level laser therapy
enhancement of ATP synthesis
stimulated vasodilation via increased histamine, NO and serotonin
beneficial acceleration of leukocytic activity
converting prostaglandin into prostacyclin
reduction in interkeukin-1
enhanced lymphocyte response
temperature modulation
stabilization of cellular membrane
mechanism of biological effects of laser
photons absorbed by the tissues
stimulates metabolic processes and cell proliferation through synthesis of nucleic acids and enhanced cell division
alter molecular level activity
photostimulation (photobiomodulation)
the process where a chain of chemical reactions is triggered by exposure to light
stimulation of the respiratory electron transport chain results in 2 major events
light changes the reduction/oxidation status of the mitochondria which leads to enhanced ATP synthesis
the activation of sodium/potassium pump alters the cell membrane permeability to flow of claicum
what are the primary effects of photobiostimulation?
direct interaction of photons with cytochromes
what are the secondary effects of photobiostimulation?
occur in the same cell in which photons produced the primary effects
induced by primary effects
cel proliferation
protein synthesis
degranulation
growth factor secretion
myofibroblast contraction and neurotransmitter modification
depending on the cell type and its sensitivity
tertiary effects of photobiostimulation
are the indirect responses of distant cells to change in other cells that have interacted directly with photons
least predictable
indications
wound healing TMD myofascial pain osteoarthritis RA tendinopathy trigger points epicondylitis neck and low back pain
class I FDA classification
safe under reasonably foreseeable use
class 1M
safe except when used with optical aids
Class II
hazardous if directed continually into the eye
class III
moderate risk to retina but not to the skin or tissues. operator and patient must wear protective eye wear
class IV
can cause damage to eyes, skin burns, fire hazard
contraindication for laser therapy
cancer pregnancy direct exposure to eyes areas of active hemorrhage over the thyroid gland directly over open wounds, unless covered with a clear protective barrier epileptic patients
super pulsed laser
pulses or bursts of energy with higher peak power and less thermal effects
stimulatory frequencies
lower frequencies are termed biostimulatory
arndt schultz principle
biological reactions are not only dictated by dose, but the rate at which the energy is delivered
