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Low Level Light Therapy
sponsored by
American Society for Photobiology
Low Level Light Therapy is the application of very low power red or near infrared light for wound healing or other therapeutic purposes.
Ask the Experts
Q: What is special about a red laser or LED? Why can't sunlight do the same things?
A: Sunlight contains ultraviolet-B and ultraviolet-A radiation, visible light, and infrared radiation. Different wavelengths can have a different biological effects; some effects are positive and some effects are negative. Red light can penetrate deep into tissues (the longer the wavelength, the deeper the penetration) and specifically targets a light-absorbing chromophore in the mitochondria.
- Dr. Joan Roberts, Professor of Chemistry and Chair, Department of Natural Sciences, Fordham University
Q: LLLT has been shown to stimulate cell proliferation. How, then could it function as a cancer treatment?
A: It is not difficult to see why light can stimulate and inhibit-i.e., modulate-cellular process. Tissues are made up of cells that are, in essence, energy-dependent electrochemical systems. Low-doses of light, particularly in the red to near infrared segment of the electromagnetic spectrum, are known to stimulate cell process that can drive proliferation. Conversely, higher doses can induce the opposite, inhibitory result, due to toxic effects that can be detrimental to both healthy and diseased cells. Yet, interestingly, our group has demonstrated that a singular modulated near-infrared low-energy laser can induce a significant increase in tumor cell death (i.e., necrosis and apoptosis) without damaging non-neoplastic peripheral cells. This is notable since cancerous cells exhibit not only a capacity for excessive proliferation but also a resistance to apoptosis. Our clinical results, which are in accord with subsequent in vitro studies by other groups, are explained by more than the particular characteristics of the treatment studied. Tumor cells have high levels of entropy and low energy states that translate into injury potentials of as much as 1.5 V (roughly the equivalent of one AA battery) compared to peripheral non-neoplastic cells. Such differences in electrochemical potential lead tumors to have a confirmedly higher sensitivity to light, which depending on the parameters used, can drive physiological self-destruction mechanisms in mutated (cancerous) cells. Indeed, it has been recently found that necrosis and apoptosis are both triggered by organisms as physiologic responses to anomalous cell behavior. Thus, while apoptotic and necrotic mechanisms are complex and still not fully understood, light has the potential -as demonstrated by our studies- to selectively activate them; effectively turning the organisms own weaponry into a novel cancer therapy.
- Elizabeth Rodríguez de Santana, M.D. and Luis A. Santana Blank, M.D., Fundalas, Foundation for Interdisciplinary Research and Development
We welcome your questions and comments! Please direct these to the LLLT webmaster: Dr Linda Jones.