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Introduction to Laser Therapy

Quick Introduction to Class 4 Laser Therapy

Laser Therapy or PhotoBioModulation Therapy is now a well recognised form of Therapy for damaged tissues and structural components(eg joints, bones, ligaments and muscles) There is a wide range of devices available ranging from simple home use devices to extremely powerful Class 4 devices that can be used on almost any animal of any size. More recently there has been an increased use of Laser machines in conjunction with Acupuncture and even as a replacement for  traditional Acupuncture.

First of we need to give a quick explanation abut the types of Laser machines available(ignoring less than Class 3 devices):

  • Class 3 machines can produce output at a MAX of 0.5W. This means that they will take a long time to achieve a therapeutic dose in any animal. It also means they are “relatively” safe.
  • Class 4 machines are defined as producing >0.5W and there are machines available with the ability to produce as high as 60W+ continuously. Some Class 3 suppliers will claim that these machines are “dangerous” but if they are used responsibly then there is no problem whatsoever.
  • Some manufacturers use an array of Class 3 diodes to get a higher overall power output but the individual diode output is still only <0.5W
  • Some manufacturers quote “Peak” output as a very high number but then report the average output as a very low number, making it no better than on of the Class3 array machines.

 Why does power matter?


When applying Laser treatment there are several “parameters” that need to be considered because

Dosage(Joules)=Power(Watts) x Time(seconds)


Depth of penetration is dependent on Power output. No amount of extra time will cause the Laser to penetrate deeper so an array of Class 3 diodes will not improve penetration.


Different Wavelengths provide slightly different benefits, although this tends to be less important than the 3 above since all the machines tend to use the ideal Wavelength/s as standard.

Recently it has become popular to add “Multi-Phase” but at the end of the day the first 3 parameters are the most important. When using the machine you would be setting a dosage using these parameters and not concerning yourself with wavelengths or phases as they will be set automatically by the machine itself.

 Typical Treatment examples

Here are some examples, the second being a typical medium to large sized dog:

600J is suitable for a small dog iliopsoas or I.V.D.D presentation.

A 1W (max) Class 4 machine will need a 10 minute treatment time versus a Class 4 30W Laser easily delivering 5W needing only TWO minutes od treatment

Now consider if you want to deliver 1600J to a larger dog eg. a 30kg dog with Stifle problem


A 1W (max) Class 4 machine takes 26:40 minutes versus 30W Laser, delivering only 8W, takes 3:20 minutes to deliver the same Joules. Additionally the 8W delivery will achieve a much better penetration of the tissues.

For even larger animals, you can simply increase the power, without needing to increase the time. In our experience most animals will sit still for up to 6-8 minutes. Vets/Nurses can fit in lots of 3-8min laser sessions in a day’s work. (We easily paid for the machine cost in < 12 months)

However, neither the pet nor the Vet nor the Tech/Nurses are quite so keen when asked to sit and reduce productivity for up to 30 minutes at a time, as is required with less powerful, (sometimes) cheaper machines. Class 4 machines can do all that a Class 3 machine does in a much shorter time, plus they have the scope to increase power to treat a wider range of patient sizes and ailments.


The information above was contained in a contribution to the CVE edition December 2021 and you can view the whole thing here for free:


Further reading

If anyone wants to learn more about using Laser Therapy then these are excellent resources. They are what I recommend to all new users:



There are other courses provided by them and elsewhere that take more time to complete. They provide courses for Vets and Nurses/Techs/Trainers.


This book is  great reference tool:


(cheaper on Ebay)


Our Vets1Laser Options

We can supply 2 and 4 wavelength Vets1Laser models and they are both MultiPhase. Our prices are based on the 810nm/980nm Dual Wavelength model which provides the optimal Wavelengths at the full 15W per Wavelength for maximum benefit.

 We can also supply a Dual function Laser machine which can be used for complex Laser Surgery OR Laser Therapy simply by quickly swapping the Optical Cable output.

If you want to discuss more you can contact us through the Contact page.

Remember- POWER is your friend when you are using these devices for Laser Therapy. 

Bigger animals need more power to save YOUR time!