العلاج بالليزر منخفض المستوى

Low Level Laser Therapy (LLLT)

• LLLT, sometimes known as Low Level Light Therapy or photobiomodulation (PBM), is a low-intensity light therapy.
• The effect of LLLT is photochemical, not thermal.
• Light triggers biochemical changes within cells, similar to photosynthesis in plants.
• Cellular photoreceptors absorb photons, triggering chemical changes.

History of LLLT

• In 1903, Dr. Nils Finsen won a Nobel Prize for using concentrated light to treat diseases, especially lupus vulgaris.
• In 1967, Mester E et al. discovered the phenomenon of "laser bio stimulation."
• In 1999, Whelan H et al. researched the use of LEDs for medical applications in space.
• Over 400 Phase III randomized, double-blind, placebo-controlled trials have been published, accompanied by over 4000 laboratory studies.

Mechanisms of LLLT

• Mitochondria are cellular power plants.
• LLLT plays a role in regulating oxidative stress, calcium metabolism, and apoptosis.
• In photobiomodulation (PBM), chromophores in mitochondria absorb light photons.
• Cytochrome c oxidase (COX) is the primary photo-acceptor for the red-NIR wavelength range in mammalian cells.
• Cellular signaling, nitric oxide (NO) dissociation, and increased ATP are also involved.
• Nitric oxide (NO) produced in mitochondria can inhibit respiration by binding to COX.
• Other signaling molecules include ATP (Adenosine Triphosphate), ROS, and Ca.

Instrumentation

• LLLT devices typically use low-power lasers or LEDs.
• The power range is 10mW-500mW
• Wavelengths used are between 660nm and 905nm.
• LEDs and SLDs treat superficial tissues, like wounds.
• Lasers are more effective for deep tissue.

Parameters of LLLT

• Wavelength: 630 nm
• Energy density: 3 to 10 J/cm².
• Power density: TEM00, TEM01, TEM10
• Bunsen Roscoe Reciprocity Law: Irradiance and exposure time are proportionally related, for a fixed photochemical effect.
• Example - 6 J/cm2 delivered in 1 second with a 6W/cm2 irradiance is equivalent to 6 J/cm2 delivered in 60 seconds with a 100mW/cm2 irradiance.
• Optical properties of tissue: influence how light interacts with tissue.
• Treatment duration: 30 seconds to 1 minute per point. From one to 10 to 15 points.
• Pulsed vs Continuous: Power can be periodically interrupted for a brief time. When pulsed, the average power decreases with higher pulse frequency. Pulse frequency determines the number of laser pulses per second.
• Clinical targets: include the site of injury, lymph nodes, nerves, and trigger points