Low Intensity Laser Therapy Basics and Clinical Applications

Abstract

Light in its various forms has been used for healing from the time of the ancient Egyptian and Greek civilizations.(1,2) With recent advances in the engineering of devices and the development of appropriate protocols for effective therapeutic application of light, dramatic benefits and treatment of many complex medical conditions are now achievable.(3-5) The word LASER is an acronym for Light Amplification by Stimulated Emission of Radiation. A laser produces photons of light with specific characteristics.(1) These include: Monochromaticity: In laser light, all electromagnetic waves have the same wavelength and color. Coherence: All the photons in laser light oscillate in the same phase. Directionality: Due to the coherence factor light is also highly directional. Intensity: the high intensity produced in a small area.(1,4,5) High power or thermal lasers can produce a substantial amount of heat. This destructive potential makes high power laser a key component in industrial applications such as cutting and welding.(2,3) Because thermal laser combines power and precision, it also has many beneficial uses in medical applications.(1) Unlike thermal lasers, the low intensity laser beam is “soft power” and does not produce heat. Low intensity laser energy initiates and stimulates many beneficial physiological processes within the cell.(6-8) In essence it promotes the healing of damaged cells which makes it applicable in the therapy of many pathologies. Moreover, it is nondestructive with regard to the target tissue.(8,9) Many terminologies are used to characterize Low Intensity Laser Therapy. Many synonyms commonly used, particularly in the literature include photo bio-stimulation, light therapy, phototherapy,laser therapy, soft laser therapy,cold laser therapy,laser light therapy,low level or energy laser,low energy photon therapy,soft tissue laser therapy,low reactive laser therapy and therapeutic laser.(1,9) Laser therapy is the use of monochromatic light emission from a low intensity laser diode (250 milliwatts or less) or an array of high intensity super luminous diodes (providing total optical power up to the 2000 milliwatt range).(9,10) Based on experience, it is clear that laser therapy above 250 milliwatts, even if used for milliseconds, can result in tissue damage, but below 250 milliwatts, using proper frequencies, duty cycles and controlling a number of other parameters, tissue stimulation can be advanced in a cumulative pattern, rather than produce inhibition of healing, which may occur at higher power settings.(10) The light source is placed in contact with the skin allowing the photon energy to penetrate tissue, where it interacts with various intracellular biomolecules resulting in the normalization of cellular components. TThere are JLMS 2010; 1:31-4