There are so many different wattages that it is very confusing because with each wattage, I have to figure in if the laser is pulsed or is continuous and know many other things than just knowing the wattage. Maybe the laser has is a 30 watt laser but only has a 12 watt continuous but a 30 watt peak.
The higher the wattage the more joules per minute the laser can deliver especially when I want to raise the voltage of my nerve cells. Healthy nerve cells tend to be at about -70 mV, and fire at about -20 mV. Compromised cell membranes have a lowered threshold as their resting potentials average around this -20 mV range. That means that normal non-noxious activities produce pain. Laser therapy can help restore the action potential closer to the normal -70 mV range.
How much power is enough?
The FDA has established power classes for all laser devices on order to define safety requirements for manufacturers and users. These ratings are not specific to medical devices. Most LLLT device are either Class 3R, Class 3B or Class 4. It is important to note that some of these ranges are huge, so comparing LLLT device power on the basis of the Class is not meaningful. For example, Class 3B is for devices in the range of 5mW to 500mW, a range of 100 times! Power output comparison should be done on the basis of maximum average output power in Watts or milli-Watts, not the class.
A lot of work has been done to try to determine an optimum dose for laser therapy treatment. It would be valuable as a practitioner to have a number, say 5J/cm2. Such a number would allow the development of standardized protocols and would allow manufacturers to build this into their devices to improve ease of use. Unfortunately no such number exists. The reason why it is so difficult to determine a range is because the requirements vary so much according to the treatment modality and wavelength.
Power requirements for infrared LLLT devices
When using an infrared laser, the treatment is closely related to therapeutic heating similar to an infrared heat lamp. (This is also the basis upon which many LLLT devices obtain FDA clearances.) When using infrared, more power is usually desirable with practitioners, since this reduces treatment time to produce the same heating effect. So a 10W infrared laser is better than a 5W laser. Why not 20W or 30W? Higher power lasers present greater hazards. For example, at 20W the heat is sufficient to burn tissue if the treatment heat is not kept in constant motion. The 10W to 15W range appears to be the sweet spot from the perspective of efficiency and cost. Even at this power range it is important that the output from the laser diodes is de-focused so that the power is evenly dispersed over an area, rather an a small spot.
A note on power ratings. Special consideration is required for "pulsed" or "super pulsed" infrared LLLT devices. Such a device might claim a power output of 10W. This rating is misleading because the diode is pulsed (at very high frequency) and this is the power only when it is on. Pulsed laser diodes are designed so that they require a long recovery period after each pulse, so although it produces 10W when on, it is off for much longer. The net result is that the average output power could be 1/1000th of the peak power at less than 10mW. When evaluating an infrared LLLT device, be sure that you know the maximum average power rating.
Power requirements for red LLLT devices
Clinical use of red lasers for diagnostics and healing reveal that there is more at play than simple heating. There is a reaction of the cells to the actual light - both the frequency and coherency. Many people can feel when a red laser of less than 5mW is shined on their palm. To put that in perspective a light bulb is around 60W, producing it 10,000 times more energy. This sensation is absent when using infrared light (laser or otherwise), or other forms of light (eg from an LED). Nobody knows why red laser light laser has this effect, or why it can accelerate healing and tissue development. Many theories exist, but these are speculative. What is important to you, the practitioner, is that the results are positive and repeatable.
The majority of research and clinical use has been in the Class 3R range (less than 5mW). Some devices use red lasers at the lower end of the Class 3B range at up to 20mW. There is some clinical evidence to suggest that efficacy diminishes above 15mW. The power requirements for a red laser used for healing and diagnostics are therefore vary different to infrared. Most notably too much is unnecessary and is actually less effective. See my new page on the types of lasers in each wattage class.
Peak VS Average Output Scams:
Which is more powerful?
15W peak " Super Pulsed" or a 30W continuous wave diode laser?
Enter your answers and under which circumstances each one would be more powerful.
Doctors should know this stuff before buying a laser.