Page 577 - WSAVA2018
P. 577

used for superficial tissue and longer wavelengths used to penetrate deeper tissues.
· In general, wavelengths for spe- cific conditions are as follows:
· 904/905nm is better for pain
· 808-860nm is better for inflammation
· 600-700nm is best for skin lesions and antimi- crobial effects
· Spatial coherence: the degree to which light is focused in a beam
· Temporal coherence: the degree to which light has a single frequency.
· The critical difference between sunlight and laser therapy is spatial and tem- poral coherence, meaning that light is focused at a particular wavelength on an intended spot. Therefore, the dose is narrowly applied to a therapeutic window as dictated by the properties of light interaction in a particular tissue.
· Irradiance: power of laser divided by spot size; calculated as Power (W)/Area (cm2)
· Power Density and Light Energy: power is mea- sured in Watts (W), which is defined as one joule per second (W= J/cm2). Light energy is measured in Joule (J). A joule is therefore a unit of energy required to produce one watt of power for one second (1 Joule = 1 Watt x 1 second).
· The total energy transferred to the tissue is reflected in J/cm2 whereas the irradiance of a laser is expressed in W/ cm2.
· A higher-powered laser can produce more energy per unit of time, which allows it to deliver laser energy faster, as well as to cover a larger treatment area by using a larger beam diameter.
· Power has absolutely nothing to do with depth of penetration, or targeting of specific tissues.
· The total dose of visible or infrared light in a human spending one hour outdoors would be about 180 J/cm2.
· Current Dosage Recommendations
· Acute conditions, superficial wounds, or inflammatory condi- tions: 1-4 Joules/cm2.
· Pain, chronic conditions, or
deep seated conditions: 6-10 Joules/cm2
· Deep seated, chronic, or severe infections: 10-30 Joules/cm2.
· A 3 X 5 card, an average man’s palm, or a CD is approximately 100 cm2. A quarter is about 5 cm2.An “Oreo” is about 25 cm2.
Your Singapore, the Tropical Garden City
Laser Classification
The laser classification system defines the amount
of power emitted; class IIIa emits (1 to 5mW output),
class IIIb (5 to 500mW output), and class IV (>500mW output). Class IIIb lasers and Class IV lasers are the most commonly- encountered in veterinary practice. The efficacy of class IIIb and class IV laser therapy has been documented.1-3 Current thought is that physiologic effects are seen with both high- and low-power settings.2,3 Not all therapeutic lasers are created equal, so it is important for veterinarians to be educated about the science and safety of therapeutic laser application. Veterinarians must do your homework so to not be seduced by marketing materials, as well as be prepared to continue learning as new information about applications becomes available.
Is the laser really doing anything?
Therapeutic Laser is used for three main purposes:
1. To promote wound healing, tissue repair, and the prevention of tissue death;
2. To relieve inflammation and edema because of injuries or chronic diseases;
As an analgesic and a treatment for other neurological problems.
These applications appear in a wide range of clinical settings, ranging from dentistry, to dermatology, to rheumatology and physiotherapy. The primary effects of photobiomodulation based on the current experimental literature include:
Cellular Effects:
a. Increase of adenosine triphosphate (ATP) production
b. Increase of cell membrane pump function c. Increase of cell respiration
d. Production of reactive oxygen species
e. Reduces the production of substance P
f. stimulates long term production of nitric oxide
g. decreases the formation of bradikynin, histamine, and acetylcholine

   575   576   577   578   579