Laser
The world "Laser" is actually an acronym for "Light Amplification by Stimulated Emissions of Radiaton". The principals behind laser were first outlined by Albert Einstein in 1917 with the first laser device being created by Maiman in the 1960's. We now have high and low power lasers. The benefits of low level laser therapy (LLLT) for soft tissue healing were published by MEster in the 1960's. NowLLLT is frequently used in Europe, Canada, and Australia. In 2002 in the United States, the FDA aproved the use of Gallium aluminum arsenide laser for the use of pain relief. Since then, there has been a dramatic increase in the clinical use of lasers.
How it works:
An atom absorbs energy, making electrons move from a low energy to high energy orbit. Thisenergy is released as photons as electrons return to normal so laser is made by the "relaxation" of electrons. Lasers can be visible red light (gaseous Helium Neon AKA HeNe) or invisible/near infrared light (Gallium arsenide AKA GaAs). The latter uses an LED light for safety so the user is able to see where the beam is pointing. Where lasers are monochormatic, coherent, and directional, LED light is only directional but believed to hae the same effect at the same wavelength as laser.
Effects of Laser & Light
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Promote ATP Production
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Promote collagen production
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Modulate inflammation
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inhibit bacterial growth
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promote vasodilation
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Alter NCV and regeneration
Indications
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Soft Tissue Healing
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Improved tissue repair by increased collagen synthesis, rate of healting, wound closure, tensile strenght, and reduced healing time
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Parameters:
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5-24 J/cm2
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Arthritis
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Beneficial for RA, but conflicting results for OA
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Parameters are unclear
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Lymphedema
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For treatment of mpostmastectomy lymphedema
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Parameters
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1.5 J/cm2, area of 3 cm2, 3 times per week for a total of 3 weeks for 1-2 cycles
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Neurological conditions
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Based on success of treating carpal tunnel syndrome
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Ongoing research into the treatment for diabetic peripheral neuropathy
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Parameters:
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5J for 5 weeks (90 mW for 33 seconds)
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Pain Management
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overall positive effect on pain for numerous conditions
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Neck Pain
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Immediate pain reduction for acute neck pain, up to 22 weeks post treatment for chronic neck pain
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Elbow tendinopathy
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LLLT at 904 nm and 632 nm gave short term pain relief and less disability
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Parameters:
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904 nm: 0.25-1.2 J/cm2
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632 nm: 6 J
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Achilles Tendinopathy
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Reduced prostaglandin E2 concentrations after LLLT, reducing pain and inflammation in Achilles tendinitis
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Parameters:
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5.4 J, 20 mW/cm2
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Plantar Fasciitis
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Decreased VAS and increased FFI for up to 6 months in patients with chronic platar fasciitis
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Parameters:
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1.4 J/cm2, 17 mW, 635 nM, 2x/wk/3wks
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*Click here for more parameter recommendations from the World Association for Laser Therapy (WALT)
Dosimetry
The dosage is usually measured in Joules/cm2. The machine will calculate treatment time based on the power of the machine. Higher power units will have shorter treatment times. Wavelength will determine the depth of penetration. The shorter the wavelength, the less frequency, and therefore the less penetration the laser will have into the tissue. The only way to change the wavelength is to switch out the size of the probe being used to administer treatment.
