Infrared (IR) is a type of electromagnetic radiation, including wavelengths between the 780 nm to 1000 μm. IR is divided into different bands: Near-Infrared (NIR, 0.78~3.0 μm), Mid-Infrared (MIR, 3.0~50.0 μm) and Far-Infrared (FIR, 50.0~1000.0 μm) as defined in standard ISO 20473:2007 Optics and photonics — Spectral bands . Several studies have reported that IR can improve the healing of skin wounds, photoprevention, relieve pain, stiffness, fatigue of rheumatoid arthritis, ankylosing spondylitis, potentiate photodynamic therapy, treat ophthalmic, neurological, and psychiatric disorders, and stimulate the proliferation of mesenchymal and cardiac stem cells [1–9].
Low-level light therapy (LLLT) is defined as “Treatment using irradiation with light of low power intensity so that the effects are a response to the light and not due to heat. A variety of light sources, especially low-power lasers are used.” in the Medical Subject Headings (MeSH) Descriptor Data 2017. Photobiomodulation (PBM) therapy is “A form of light therapy that utilizes non-ionizing forms of light sources, including lasers, LEDs, and broadband light, in the visible and infrared spectrum. It is a nonthermal process involving endogenous chromophores eliciting photophysical (i.e., linear and nonlinear) and photochemical events at various biological scales. This process results in beneficial therapeutic outcomes including but not limited to the alleviation of pain or inflammation, immunomodulation, and pro-motion of wound healing and tissue regeneration.” as a defined in Anders et al. . It is now agreed that “PBM therapy” is a more accurate and specific term for the therapeutic application of low-level light compared with “LLLT”.
The objective of this study was to evaluate the effects of LED on burns healing. Five patients with skin burns were submitted to photobiomodulation by LED, GaAsIP diode, (λ 658 nm) with 40 mW, 7 J/cm2 on every other day. Biopsies of burned skin were performed and the healing process was photographed. Patients with bilateral burns were used as self-control, having one limb being irradiated and the contralateral limb irradiated with placebo. The burns treated with LED showed higher epithelization, with keratinocytes and fibroblasts proliferation, increased collagen synthesis, decreased pain, and pruritus. In conclusion, there was a faster clinical improvement in the irradiated limbs.
Holanda VM, Chavantes MC, Wu X, Anders JJ. The mechanistic basis for photobiomodulation therapy of neuropathic pain by near infrared laser light. Lasers Surg Med. 2017;49(5):516–524. doi:10.1002/lsm.22628
Background and objective: Various irradiances have been reported to be beneficial for the treatment of neuropathic pain with near infrared light. However, the mechanistic basis for the beneficial outcomes may vary based on the level of irradiance or fluence rate used. Using in vivo and in vitro experimental models, this study determined the mechanistic basis of photobiomodulation therapy (PBMT) for the treatment of neuropathic pain using a high irradiance.
[Purpose] To compare two platelet-rich plasma kits with different platelet concentrations for treatment of knee osteoarthritis. [Subjects and Methods] Male and female patients with knee osteoarthritis who had confirmed diagnosis with X-ray and magnetic resonance imaging were included in this retrospective study. Eligible patients were divided into two groups: Group I, which received platelet-rich plasma kit I, and Group II, which received platelet-rich plasma kit II. Platelet concentrations of both kits were measured by manual counting. For each group, platelet-rich plasma kit was injected twice with a one-month interval between injections.