Low level laser therapy
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Low level laser therapy (LLLT, also known as photobiomodulation, cold laser therapy and laser biostimulation) is an emerging medical and veterinary technique in which exposure to low-level laser light or light-emitting diodes are used to stimulate or inhibit cellular function possibly leading to beneficial clinical effects.[1] The technique is also known by the more ambiguous terms laser therapy and phototherapy (though the latter more accurately refers to light therapy), which may also be used to describe other medical techniques. Rationales for suggesting particular combinations of wavelength, intensity, duration and treatment interval are still being refined.[2]
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[edit] History
In 1967 a few years after the first working laser was invented, Endre Mester in Semmelweis University experimented with the effects of lasers on skin cancer. While applying lasers to the backs of shaven mice, he noticed that the shaved hair grew back more quickly on the treated group than the untreated group.[3]
[edit] Clinical applications
Clinical applications that show some potential of effectiveness include treating soft tissue injury, chronic pain, and wound healing. Less likely are effects on tinnitus and nerve regeneration. Resolution of viral and bacterial infections has been claimed, but no plausible mechanism for this has been proposed. One clinical application of interest is the treatment of inflammation, where the possible anti-inflammatory effect of location-and-dose-specific laser irradiation is being evaluated in comparison with NSAIDs. [4]
[edit] Mechanism
Certain wavelengths of light at certain intensities (or irradiance to use the technically correct term) delivered by laser, LED or another monochromatic source may affect tissue regeneration, inflammation, or pain.[5] The exact mechanism is still being explored and debated but it is likely that the mechanism is photochemical rather than heat-related.[citation needed] Observed biological and physiological effects include changes in cell membrane permeability, up-regulation and down-regulation of adenosine triphosphate and nitric oxide.
The factors of wavelength, effective dose, dose-rate effects, beam penetration, the role of coherence and pulses (peak power and repetition rates) are still poorly understood in the clinical setting. Laser average power is typically in the range of 1-500 mW; some high peak power, short pulse width devices are in the range of 1-100 W with typically 200 ns pulse widths. The average beam irradiance then is typically 10 mW/cm2 - 5 W/cm2.[citation needed] The wavelength is typically in the range 600-1000 nm (red to near infrared) but some research has been done and products are available outside this range.
[edit] Safety
During the use of lasers; doctors, operator, and patient normally wear dense filter spectacles in case of accidental or reflected exposure to avoid damaging the eye.
[edit] See also
[edit] References
- ^ "Mechanisms for low-light therapy". Photonics West BiOS 2007, Conference #6428. http://spie.org/Documents/ConferencesExhibitions/BiOS07-Abstracts.pdf. Retrieved on 2007-10-16.
- ^ "Abstracts from 7th international congress of the world association for laser therapy october 19-22, 2008". Photomed Laser Surg 27 (1): 155–209. February 2009. doi:. PMID 19250054.
- ^ Mester, E.; Szende, B., and Tota, J.G. (1967). "Effect of laser on hair growth of mice". Kiserl Orvostud 19: 628–631.
- ^ Bjordal JM, Couppé C, Chow RT, Tunér J, Ljunggren EA (2003). "A systematic review of low level laser therapy with location-specific doses for pain from chronic joint disorders". The Australian journal of physiotherapy 49 (2): 107–16. PMID 12775206.
- ^ Abramovitch-Gottlib L, Gross T, Naveh D, Geresh S, Rosenwaks S, Bar I, Vago R (2007). "Low level laser irradiation stimulates osteogenic phenotype of mesenchymal stem cells seeded on a three-dimensional biomatrix". Lasers in medical science 20 (3): 143–57. doi:. PMID 16292614.
[edit] External links
- World Association for Laser Therapy
- USA National Institute for Health database
- The effect of 300 mW, 830 nm laser on chronic neck pain: a double-blind, randomized, placebo-controlled study.
- Low-Level Laser Therapy in acute pain: a systematic review of possible mechanisms of action and clinical effects in randomized placebo-controlled trials, .
- 830 nm laser irradiation induces varicosity formation, reduces mitochondrial membrane potential and blocks fast axonal flow in small and medium diameter rat dorsal root ganglion neurons: implications for the analgesic effects of 830 nm laser.
- Low-level laser therapy for zymosan-induced arthritis in rats: Importance of illumination time.
- Low-level light stimulates excisional wound healing in mice.
- The Laser Therapy Handbook - Tuner, Jan and Hode, Lars,
