Educational Guide

Laser and Light Therapy Dosages

Understanding the science behind effective treatment protocols

Dosage is THE single most important factor in determining outcomes in laser and light therapy.

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The Dosage Sweet Spot

Too low = slower results. Too high = good pain control but not optimal recovery. Optimal = fastest healing.

Calculating Dosage

Energy density is measured in joules per square centimeter at target depth. European standards typically range from 4-8 J per square cm.

Step 1: Total Dosage at Depth Total Dosage = Desired Energy Density x Treatment Area

808/810nm is approximately 3x better than 850nm and 30x better than 980nm at penetrating tissue.

Step 2: Surface Dosage Surface Dosage = Depth Dosage / Wavelength Efficiency / Source Efficiency
Source Efficiency: Lasers (coherent) = 100% | LEDs (non-coherent) = 1-10%
Step 3: Adapted Dosage Adapted Dosage = Surface Dosage x Skin Factor x Size Factor
Step 4: Treatment Time Treatment Time (sec) = Adapted Dosage / System Delivery Rate

A 10-watt system delivers 10 J/sec. More power = shorter treatment times, not better results.

Example 1

Arthritic Finger

Target Density: 4 J per sq cm
Treatment Area: 3 sq cm
Max Depth: 1.6 cm (80 percent efficiency)
Laser: 0.1W 810nm
Patient: Light skin, average size
Dosage at depth = 4 x 3 = 12 J
Surface dosage = 12 / 0.8 / 1.0 = 15 J
Adapted dosage = 15 x 1.0 x 1.0 = 15 J
Treatment time = 15 / 0.1 = 150 sec (2.5 min)

Even Class 1/2 lasers work well on easier cases - which explains good reviews for lower-power systems.

Example 2

Low Back (Complex Case)

Target Density: 4 J per sq cm
Treatment Area: 129 sq cm
Max Depth: 30 cm (20 percent efficiency)
Laser: 10W CW 810nm
Patient: Large (1.1x), olive skin (1.15x)
Dosage at depth = 4 x 129 = 516 J
Surface dosage = 516 / 0.2 / 1.0 = 2,580 J
Adapted dosage = 2,580 x 1.1 x 1.15 = 3,264 J
Treatment time = 3,264 / 10 = 326 sec (5.4 min)

Same case with 980nm: Only 1% reaches 30cm - needs 60,000 J

Same case with 1W laser: Would require 54 minutes

The Range of Equipment

Lower-power systems work on shallow, small problems but may not accumulate sufficient dosage for larger, deeper issues.

Class 1/2
Class 3B
Class 4
Session Dosage
0.2-50 J
200-500 J
2000-60000 J
Treatment Time
10+ min
12 min
5 min

Peak Outcomes

The Arnold-Schultz diagram shows peak cellular stimulation at optimal dosage. This is why the industry is moving toward more powerful equipment.

Need Help With Dosage Calculations?

We can help you understand optimal protocols for your practice.

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