Laser Therapy Blog

Just like the prescription of drugs there is a target dose of laser therapy energy; where oral medications are measured in mg, laser therapy dose is measured in Joules per square cm.  Class IV laser therapy target doses are determined by the type of condition being treated, the depth of the target tissue and the patient’s individual absorption characteristics.

Deep conditions are recommended to receive a target dose of 8-10 Joules/cm², this enables a therapeutic amount of light to penetrate to the target tissue.  Superficial conditions or areas that are boney with very little soft tissue (hands, knees, elbows), are recommended to receive a target dose of 4-6 Joules/cm².

Some Laser Therapy devices come with preset protocols to help you determine target dose for a wide variety of conditions.  LightForce Therapy Lasers contain Influence Technology that adjusts the protocol based on your patient’s individual absorption characteristics (skin color, body type, height, and specific condition being treated).  This information allows the therapy laser to adjust the amount of the 980 nm and 810 nm therapeutic light to ensure optimal penetration and delivery of a therapeutic dose.

The key to dosage is that it is measured in Joules per cm2 and to achieve consistent results you must provide a therapeutic dose (8-10 J/cm² for Deep Conditions and 4-6 J/cm² for Superficial Conditions).  Make sure you understand the difference before you invest in laser therapy equipment.  Not all lasers are the same and not all Class IV laser therapy devices are the same either.

There are many different types of therapy lasers.  Class IV lasers for pain, Class IIIb therapy lasers, Class III laser therapy equipment, even class II lasers.  One parameter that separates these lasers from one another is power.  What role does power play in achieving clinical results?

Power impacts the functional depth of penetration of the laser light.  The combination of treatment time and power determines the tissue depth that receives a therapeutic dose of energy.  If the therapy laser equipment you are using has low power, the total number of Joules you can deliver to relevant depths for treating most musculoskeletal conditions in a realistic treatment time is very low.

For example, if we want to treat the thoracic spine on a 200-pound male and we determine that our treatment area is 300 cm², since it is a deep condition we want to treat with 10 Joules/cm² our target dose is 3,000 Joules (300cm² x 10 J/cm² = 3,000 J).  Below is an example of how long it would take to deliver 3,000 J of therapeutic energy with 4 different lasers of variable power:

5mW Laser = 10,000 minutes (166.7 hours)
500mW Laser = 100 minutes (1 hour 40 minutes)
3W Laser = 16.7 minutes
10W Laser = 5 minutes

Therefore, treating with a low powered laser will cause you to deliver less than the identified therapeutic dose of 3,000 Joules simply because the treatment time is unrealistic.  LightForce Therapy Lasers enable you to deliver power from 500mW to 15 Watts giving you the flexibility you need to give every condition the therapeutic dose it needs.

THE CLASS DIFFERENCE:  5 THINGS YOU NEED TO KNOW ABOUT CLASS III VS. CLASS IV

There is a lot of discussion about different classes of therapy lasers.  What’s the difference?  Understand these key differences before you invest in your own laser therapy equipment.

1. What the classifications actually mean?
   Class IIIb:  IIIb lasers are hazardous to the eye when viewed directly.  For visible and infrared devices emission power is limited to 0.5 W. Protective eyewear, key switch and safety interlock are required safety features.
   Class IV:  Class IV includes all lasers that emit power in excess of IIIB limitations. Eye protection is needed to limit both direct and diffuse reflected exposure. Key switch and safety interlock are also required safety features. The majority of scientific, industrial, military, and medical lasers fall into this category.
2. Power:  Class IIIb lasers are limited to powers of 0.5 watts and under, Class IV therapy lasers typically enable the user to select powers of 0.5 W – 15 W.  Increased power enables the clinician to treat a larger area in a shorter period of time – ultimately resulting in a therapeutic dose of joules to the target tissue.
3. Treatment Strategies:  Due to their power difference treatment strategies are different for Class IIIb lasers vs. Class IV therapy lasers.  Class IIIb lasers often treat a group of small points and are held in one place for the duration of the point treatment.  When treating with a Class IV therapy laser the clinician treats a much larger area, i.e. 300 cm² for a lower back; the treatment head is moved throughout the duration of the treatment to ensure a therapeutic energy is being delivered evenly to the entire area.  Class IV laser therapy can also be administered through a series of contact and non-contact handpiece attachments.
4. Dosing Strategies:  Class IIIb lasers deliver a smaller dose of joules to a smaller area of tissue.  Typically treatments are confined to discrete points.  A potential weakness of this technique is the variability of clinical results due to the exact placement of the treatment points.  The foundation of Class IV laser therapy is based on the delivery of a therapeutic dose of joules to a large area of target tissue, reducing variability in outcomes.  For example on a lower back a Class IV therapy laser would treat at 10 joules/ cm², in a 10 minute treatment session of 10 watts in continuous wave 6,000 joules of energy would be delivered to the target tissue.  It would take a 0.5 watt Class IIIb laser 200 minutes to deliver the same dose.
5. Wavelength:  Different therapeutic lasers often come equipped with different treatment wavelengths ranging from 700 nm to 980 nm.  All wavelengths in this therapeutic window target the same photo-active chromophores.  The main difference between wavelengths is the absorption of the light by tissue components such as water and melanin.  A device with a adjustable wavelengths allows you to adjust for the individual absorption characteristics of your patient.