ABSTRACT
Photobiomodulation (PBM) also known as low-level laser (light) therapy (LLLT) is approaching its 50th anniversary. In 2016, there was an international consensus to change the terminology away from LLLT and the old term "low-level", and instead use the new term "photobiomodulation". The first law of photobiology states that photons of light must be absorbed by some molecule, called as a chromophore, located within the tissue to have any biological effect. Tiina Karu working in Russia and Salvatore Passarella in Italy were the first to suggest that one of the principal chromophores responsible for the beneficial effects of LLLT was located inside mitochondria. PBM has been extensively used to treat autoimmune diseases, both in experimental animals and in humans. PBM is often used clinically to treat pain. Very often this is pain resulting from some orthopedic disorder such as tendonitis, arthritis, traumatic joint injuries.
