PHOTOMEDICINE (LASER THERAPY BENEFITS)
Primary response is elicited when photons emitted by the laser reach the mitochondria and cell membranes of underlying cells such as fibroblasts, where photonic energy is absorbed by chromophores and is converted to chemical kinetic energy within the cell. Chromophores absorb photons with wavelengths between 700 and 1200 nanometers (NIR, or near infra-red), with those in the 808nm and 980nm wavelengths being the deepest penetrating.
Secondary reactions lead to the amplification of the primary actions. A cascade of metabolic effects results in various physiological changes at the cellular level—such as changes in cell membrane permeability. Calcium is released from the mitochondria resulting in changes of intracellular calcium levels. This stimulates cell metabolism and the regulation of signaling pathways responsible for significant events required for tissue repair such as cell migration, RNA and DNA synthesis, cell mitosis, protein secretion, and cell proliferation.
Additional responses are induced at a distance from the cells in which the secondary events occur. Energized (irradiated) cells communicate with each other and with nonirradiated cells through increased levels of cytokines or growth factors, along with correlating electromagnetic energy field interactions. This intercellular communication on the cellular biochemical and electromagnetic energy field levels results in an increase in (ATP) Adenosine Triphosphate production, enhanced immune response with the increased activation of T-lymphocytes, macrophages, and number of mast cells, an increase in the synthesis of endorphins, and a decrease in bradykinin results in pain relief, and a general increase in the energy levels of targeted tissues, as well as additional beneficial interactions. While tertiary effects can be least predictable because they rely on intercellular interactions and vary according to tissue factor variables, they can be most profound and have a major effect on beneficial targeted tissue interactions.
Each tissue type has a different optical behavior; the laser energy beam is reflected, scattered, absorbed or attenuated depending primarily on the wavelength and tissue according to tissue variability factors. With increasing depth, the laser energy and power attenuates and can be compensated by higher power or therapy duration in laser devices that are capable of delivering the requisite therapeutic values.
Photonic energy absorption primarily occurs through three mediums in living tissue: water, melanin, and hemoglobin. Laser energy has unique spectral absorption properties and is pigment-oriented; in other words, wave energy is attracted to like-pigmented tissues, with therapeutic wavelengths existing in what we call the optical window, which are wavelengths between 700nM to 1200nM. The primary therapeutic wavelengths consist of: 810nM - primarily absorbed by hemoglobin, and considered the “Jack of all Trades” wavelength, 915nM - primarily absorbed by water, 980nM - primarily absorbed by plasma, and the 1064nM wavelength, which is primarily absorbed by tensile, or collagenous tissues, including tendons, cartilage, and bones.
Light (Photonic Energy) is part of the electromagnetic spectrum, which ranges from radio waves on the low end to gamma rays on the high end. Electromagnetic radiation waves, as their names suggest, are fluctuations of electric and magnetic fields, which can transport energy from one medium to another across a barrier. Visible and non-visible light is not inherently different from other parts of the electromagnetic spectrum with the exception that the human eye can detect visible waves. Electromagnetic radiation can also be described in terms of a stream of photons which are massless particles each travelling with wavelike properties at the speed of light. A photon is the smallest quantity (quantum) of energy which can be transported, and it was the realization that light travelled in discrete quanta that was the origin of Quantum Theory.