Laser is an acronym for light amplification by stimulated emission of radiation. Whilst true laser utilises a single wavelength of light (e.g., 632.8nm helium neon laser) laser diodes emit narrow bandwidths of light (e.g., 660nm +/- 5nm).
Although Einstein predicted laser, it was Theodor Maiman who created the first ruby laser in 1960. Prof Endre Mester is considered the father of photobiomodulation using low powered laser devices in the 1960’s.
A range of biological mechanisms have been identified including dissociation by photons of inhibitory nitric oxide (NO) from cytochrome C oxidase, resulting in increased electron transport, mitochondrial membrane potential and ATP production. As a result, numerous signalling pathways can be activated via reactive oxygen species, cyclic AMP, NO and Ca2+, activating transcription factors and increasing expression of genes related to protein synthesis, cell migration and proliferation, anti-inflammatory signalling, anti-apoptotic proteins and antioxidant enzymes. Thus, laser light and other narrow bands of light have been shown to benefit many conditions that have an inflammatory component or where cellular ATP production is sub-optimal.
Laser therapy has been used by physiotherapists since the late 1980s especially in pain management and tissue healing. Whilst use of electrophysical agents in physiotherapy may have recently declined, the evidence for and the use of laser is reversing the trend. Laser therapy is showing significant signs of clinical benefit in fields as disparate as neurodegeneration, neuromusculoskeletal health and cardiopulmonary care.
Description provided by Liisa Laakso of Australia
References:
Freitas de Freitas and Hamblin. 2016. Proposed mechanisms of photobiomodulation or low-level light therapy. IEEE Journal of Selected Topics in Quantum Electronics, 22(3), 348-364.
