There are many types of lasers. Each laser has different characteristics which produce a different effect. These characteristics include:
- Energy: measured in joules
- Time: Defined as the duration of irradiance of target tissue and is measured in seconds. It is also known as Impulse Duration or called “impulse width”.
- Wavelength: Penetration depth is directed by the laser emission wavelength and the type of tissue (chromophores).
- Frequency: Defined as the number of impulses emitted during the unit of time (1 second) and should reflect the condition treated.
- Power: the rate at which energy is delivered and is measured in watts.
- Fluence: Energy Density or Dose
- Irradiance (Also known as Power Density): Power delivered per unit area
- Emission Mode: Continuous Wave (CW) or Pulsed Wave (PW)
- Impulse Duration: Duration of laser emission, also called “impulse width”.
Laser therapy uses light to favor and accelerate the body’s natural healing processes. The laser beam is moved over the skin so that the light energy (photons) penetrates the tissue where it interacts with various molecules (chromophores) that cause different biological effects. It produces a photochemical, photothermal and photomechanical effect.
The energy from laser light interacts with tissue, generating biological effects:
Primary Biological Effects
Direct transfer of energy to the biological sublayers (endogenous or exogenic chromophores).
- Enzymatic activation
- Increase in ATP production
- Modulation of cellular metabolism
- Effect on pain perception threshold
Photothermic interaction is based on the conversion of option radiation into thermal energy which, at a microscopic level, occurs through the inelastic encounter between excited molecules following the absorption of photons.
- Increase in circulation
- Increased supply of oxygen and nutrients
The absorption of energy involves the formation of mechanical waves.
- Production of an extracellular matrix (important in tissue repair & regeneration)
- Acceleration of lymphatic peristalsis
- Re-absorption of edemas
- Reactivation of microcirculation