Low Level Laser Therapy LLLT PDF

Low Level Laser Therapy LLLT Third session Presented:Dr. Marjaneh Hejazi 4/5/2021 ١ Today’s content What is LLLT? History of LLLT Mechanisms of LLLT Instrumentation Parameters of LLLT Current Project Summary...

Low Level Laser Therapy LLLT Third session Presented:Dr. Marjaneh Hejazi 4/5/2021 ١ Today’s content What is LLLT? History of LLLT Mechanisms of LLLT Instrumentation Parameters of LLLT Current Project Summary 4/5/2021 ٢ 4/5/2021 ٣  ?What is LLLT Low Level Laser Therapy (LLLT) sometimes known as Low Level Light Therapy or photobiomodulation (PBM) is a low intensity light therapy. 4/5/2021 ٤ What is LLLT? The effect is photochemical not thermal. The light triggers biochemical changes within cells and can be compared to the process of photosynthesis in plants, where the photons are absorbed by cellular photoreceptors and triggers chemical changes.. 4/5/2021 ٥ History of LLLT In 1903, Dr. Nils Finsen was awarded a Nobel Prize for his contribution to the treatment of diseases, especially lupus vulgaris, with concentrated light radiation 1967 when Mester E et al. was able to demonstrate the phenomenon of “laser bio stimulation”. In 1999, Whelan H et al. presented his work on the medical applications of light emitting diodes (LED) for use on the NASA space station 4/5/2021 ٦ History of LLLT Subsequently over 400 Phase III randomized, double-blind, placebo-controlled trials have been published, with over 4000 laboratory studies of LLLT. (Pubmed.gov) 4/5/2021 ٧ History of LLLT LLLT is the application of light (usually a low powered laser or LED typically power range of (10mW–500mW). Light with a wavelength in the red to near infrared region of the spectrum (660nm–905nm), is generally employed because these wavelengths have the ability to penetrate skin, and soft/hard tissues (Figure 2) and are proven in clinical trials to have a good effect on pain, inflammation and tissue repair. 4/5/2021 ٨ 4/5/2021 ٩ Mechanisms of LLLT Mitochondria is a cellular power plant 4/5/2021 ١٠ Mechanisms of LLLT important roles in regulation of oxidative stress, calcium metabolism, apoptosis 4/5/2021 ١١ Mechanisms of LLLT In PBM, chromophores in mitochondria absorb light photon cytochrome c oxidase 4/5/2021 ١٢ 4/5/2021 ١٣ Mechanisms of LLLT Cytochrome c oxidase (COX) is the primary photo-acceptor for the red-NIR wavelength range in mammalian cells. 4/5/2021 ١٤ Mechanisms of LLLT Cellular signaling Nitric oxide (NO) dissociation Increase ATP 4/5/2021 ١٥ Mechanisms of LLLT Nitric oxide (NO) produced in mitochondria can inhibit respiration by binding to COX. 4/5/2021 ١٦ Mechanisms of LLLT Other signaling molecules are: ATP (Adenosine Triphosphate) ROS Ca 4/5/2021 ١٧ 4/5/2021 ١٨ 4/5/2021 ١٩ 4/5/2021 ٢٠ 4/5/2021 ٢١ Mechanisms of LLLT It has been observed in many studies, that LLLT exhibits a Arndt– Schultz law biphasic dose response curve 4/5/2021 ٢٢ Mechanisms of LLLT 4/5/2021 ٢٣ Instrumentation 4/5/2021 ٢٤ 4/5/2021 ٢٥  Hamblin, M.R., 2019, September. Photobiomodulation for Alzheimer’s disease: has the light dawned?. In Photonics (Vol. 6, No. 3, p. 77). Multidisciplinary Digital Publishing.Institute ٢٦ 4/5/2021 Instrumentation  Parameters of LLLT Treatment Parameters in LLLT Wavelength (nm) Power density (W/cm2) Energy density (J/cm2) optical properties of the tissue Continuous or Pulsed Treatment duration (sec or min) 4/5/2021 ٢٧ 4/5/2021 ٢٨ Parameters of LLLT: Wavelength 630 nm 4/5/2021 ٢٩ Parameters of LLLT: Energy density Numerous studies suggest that fluences ranging from 3 to 10 J cm2, at the cellular level, 4/5/2021 ٣٠ ∕ Parameters of LLLT: Power density 4/5/2021 ٣١  Parameters of LLLT: Power density (Bunsen Roscoe Reciprocity Law As long as the product of irradiance and the time of exposure is the same the photochemical effect will be the same 4/5/2021 ٣٢ Parameters of LLLT: Power density 6J/cm2(Using the same spot size) PD:100mW/cm2 PD:1W/cm2 PD:6W/cm2 T:60s T:6S T:1s 4/5/2021 ٣٣ Parameters of LLLT: Optical properties of the tissue 4/5/2021 ٣٤ Parameters of LLL Pulsed or continious The power on most LLLT devices can be periodically interrupted for a very brief period on time. This is called “pulsing”. When pulsed mode is used the average power delivered will decrease proportional to the pulse frequency that is selected. 4/5/2021 ٣٥  Setting the pulse frequency determine the number of laser pulses delivered per second during a pulsed LLLT treatment. 4/5/2021 ٣٦ Parameters of LLLT There are four clinical targets for LLLT: a. The site of injury to promote healing, remodeling and reduce inflammation. b. Lymph nodes to reduce edema and inflammation c. Nerves to induce analgesia. d. Trigger points to reduce tenderness and relax contracted muscle fibers. 4/5/2021 ٣٧ Parameters of LLLT Treatment times per point are in the range of 30 seconds to 1 minute. As little as one point may be treated in simple cases, but as many as 10 to 15 points may be treated for more complex dysfunction such as cervical or lumbar radiculopathy 4/5/2021 ٣٨  Radiation-induced OM protocol For radiation-induced OM procedure: Materials & Methods ❑ Immobilization of animals: Ketamine and Xylazine at a dose of 87 mg/kg and 13 mg/kg ❑ Irradiation by single-dose (6 MV linear accelerator) ❑ 20 Gy radiation dose delivered to induce severe OM in the grouped animals ٣٩ Figure 3.2: Irradiation of rats using 6 MV LINAC Materials & Methods ٤٠ Figure 3.11: The LED photo illumination module Summary Low level Laser Therapy has a photobiomodulation effect in tissue. Simply put, this means that a photochemical reaction is responsible for the physiologic effects of LLLT. This reaction can cause either photobiostimulation or photobioinhibition depending on the dosage of LLLT applied to tissue). Lower dosages are associated with photobiostimulation and higher doses are associated with photobioinhibition. 4/5/2021 ٤١ Summary Cells with higher numbers of mitochondria respond better to PBM than cells with lower numbers of mitochondria. The fluence J/cm² delivered is more important in determining the success or failure of an in vitro study than the irradiance mW/cm² employed. 4/5/2021 ٤٢ Summary Ineffective studies in vivo are more likely to be due to under-dosing regardless of the number of mitochondria. 4/5/2021 ٤٣