The benefits of laser therapy are dramatically evidenced with recent understanding of the mechanisms for activating healing and pain relief, and the documentation of the clinical effects of
laser therapy. However, the increasingly abundant information about lasers and laser therapy is also fraught with inconsistencies in terminology, and with marketing claims that sometimes defy logic and the laws of physics.

If you’re investing in laser therapy, start with a solid foundation of knowledge about the technology and the clinical parameters. Below are some of the initial questions we hear in our training classes.

And if you’re ready to learn more, check out the resources on the Support page of this website.

What is a laser?

L.A.S.E.R. (Light Amplification by Stimulated Emission of Radiation) is an acronym that has become a word of common use. The word LASER denotes a device that projects intense radiation from the light spectrum, producing a beam of light in which high energies can be concentrated.

In the light spectrum, laser light has the unique physical properties of coherence and monochromaticity. These are the keys to how laser light is so effective in pain reduction and healing. Monochromaticity refers to the production of a single wavelength of photons, within a very narrow wavelength range, from a laser diode. Coherence means that the photon waves are in synchronized emission with each other.

What is laser therapy?

Laser therapy, also known as low level laser therapy, phototherapy, or photobiostimulation, is the application of low power non-ablative coherent light to injuries and lesions to stimulate healing. Its use gives pain relief, resolves inflammation, and increases the speed, quality and strength of tissue repair.

Compared to other electrotherapeutic modalities (such as ultrasound and TENS), laser therapy can offer superior healing and pain relieving effects, especially in chronic problems and in the early stages of acute injuries. For treating muscle, tendon, ligament, connective tissue, bone, neural, and dermal tissues in a non-invasive, drug-free modality, laser therapy may be used as a complete system or integrated with other treatment therapies.

How does laser therapy work?

The effects of any laser therapy are photochemical – photons stimulating chemical reactions, such as the production of ATP.  Superpulsed lasers (such as the Lumix lasers) also produce photomechanical effects – photons stimulating additional intracellular reactions, such as the enhancement of gene expression.

Laser photons entering body tissues are absorbed by chromophores in the cell’s mitochondria and at the cell membrane. When chromophores absorb photons, they modulate cellular redox states and the mitochondrial respiratory chain. Within the mitochondria, the photonic energy is converted to electrochemical energy in ATP.

In the cell membrane, laser photons increase permeability, promoting physiological changes that affect macrophages, fibroblasts, endothelial cells, mast cells, bradykinin, and nerve conduction rates.

Lumix Laser Therapy

What is the best wavelength?

The best wavelength is the one that is delivered to the target tissue in sufficient quantity to achieve the desired clinical effects. Different wavelengths have different tissue absorption characteristics and corresponding different physiological effects.

The clinical and physiological effects of laser therapy are dependent on photon absorption, which is primarily dependent on 1) the tissue through which the photons are passing, 2) the emission power density and 3) the emission wavelength.

Different wavelengths are absorbed preferentially by different tissues, passing through some types of cells easily, and absorbed by others. Absorption of wavelengths effectively reduces or blocks further depth of penetration of the laser photons. For example, wavelengths that are highly absorbed by water will not penetrate vascularized tissue, and have superficial effects, effective for skin effects or for superficial acupuncture points.

The depth of photonic penetration is also driven by the power (wattage) of the laser; sufficient power is required to drive the laser energy, of any wavelength, to the clinical target tissue, with sufficient energy density to achieve significant physiological stimulation.

The use of an improper laser wavelength for the target tissue and the tissues to be penetrated en route, or insufficient power of the laser to deliver the wavelength to the target tissue, would disallow sufficient photons to reach the target area.

Different lasers emit different wavelengths, different powers of emissions, and different patterns of emission delivery, yielding differences in clinical effects. There is no “best wavelength” without considering the treatment tissue, and depth of penetration required to reach the treatment target, and capability of the laser to deliver the required emission depth and energy density.

Are your wavelengths patented?

Electromagnetic waves exist in nature and manifest specific wavelengths.  Laser emission wavelengths are not patentable, they are an inherent characteristic of the material used on the diode to create a laser emission.

How deep into the tissue can laser light penetrate?

The level of tissue penetration by the laser beam depends primarily on its wavelength, the type of tissues traversed by the laser photons, and the capability of the laser to deliver photon depth and density. For example, at the 10,600 nanometer wavelength, the wavelength of CO2 gas lasers, water absorbs virtually 100 percent of the laser photons.  Cells contain water, absorb the photons quickly, and provide the extreme cellular “heating” for a very short depth of penetration, used in soft tissue surgical applications. The 10,600 nm wavelength, traveling through naturally hydrated tissue, in a CO2 gas laser, has a very short penetration.

Similarly, 980 nm wavelength does not penetrate without heat effects (although relatively much less than 10,600 nm) and is appropriate for superficial to mid depth thermal treatments.

The depth of photonic penetration is also driven by the power (wattage) of the laser; sufficient power (peak power and average power) is required to drive the laser energy to the clinical target tissue, with sufficient energy density to achieve significant physiological stimulation.

The use of an improper laser wavelength for the target tissue and the tissues to be penetrated en route, or insufficient power of the laser to deliver the wavelength to the target tissue, would disallow sufficient photons to reach the target area.

Depth of penetration is also affected by pigmentation and foreign substances on the skin surface, because these substances absorb photons and limit depth of penetration.

Why do some lasers work better than others?

Meta-analysis of clinical studies reveal that when laser therapy is not effective, that an insufficient delivery of laser stimulation is involved.

There is a minimum energy density or dose required to achieve the biological effects of the laser light. Several factors can affect whether that minimum dose or energy density of laser light reaches the target treatment tissue.

  1. The laser effects weaken (fewer photons remain unabsorbed) the further from the treatment surface the light penetrates. Therefore, up to 99% of the laser energy can be lost en route to the tissue when the target tissue is deep below the skin surface.
  2. Laser energy can be lost when firm skin contact is not used because of the thermal effects of the wavelength used.
  3. The technology of the laser is ineffective in delivering the penetration or power density required to reach the target tissue.

Does laser go through bone?

Bone, muscles and other soft tissues are relatively transparent to therapeutic (as opposed to surgically used) laser wavelengths.  Therapeutic laser wavelengths, when properly used, can safely penetrate these tissues.

What is the therapeutic window?

The “therapeutic window” is the reason that laser therapy is effective for healing.

There exists a narrow band in the light spectrum where water is not a highly efficient chromophore, thereby allowing light energy to penetrate tissue that is rich in water content (vascularized). This narrow band, approximately from 600 to 1,200 nanometers, is the so-called “therapeutic window.” All therapeutic lasers have wavelengths within this therapeutic window.

What is the difference between Lasers and LED?

Light emitting diodes (LED) are tiny light bulbs. The illumination results from the movement of electrons in a semiconductor material.

LED’s produce incoherent light the same as an ordinary light bulb. Non-penetrating LED light works on skin level conditions.

What is the difference between superpulsed and pulsed continuous wave lasers?

The differences between the types of therapeutic lasers available vary according to the technology involved in generating the laser emission from a laser diode.  Primarily, the characteristics of the laser diodes define the laser type.

Diodes vary in their composition and capability to emit photons of specified 1) pulse duration and 2) pulse rates.

Pulse duration is the length of a single laser pulse emission from a diode. CW diodes emit pulses of milliseconds (thousandths of a second) length.  Superpulsed diodes emit pulses of nanoseconds (billionths of a second) length. These pulse durations effect thermal vs non-thermal effects of the emission.

Pulse rate is the number of pulses per second, measured as hertz (Hz) or kilohertz (kHz). A CW diode pulse rate could be as high as 10,000 Hz (10 kHz), although a CW diode pulse rate is typically 5,000 Hz.  A superpulsed diode (depending on the specific diode) may have pulse rates up to 100,000 pulses per second (100 kHz).

Different laser manufacturers choose diodes and supporting technology for different performance and/or cost considerations in designing laser devices. There are differences among CW lasers, and differences among Superpulsed lasers.

Most therapeutic lasers in the North American market are pulsed CW lasers.   For equivalent average powers, Superpulsed diodes are more expensive than CW diodes, and the laser and electronic technologies required to use Superpulsed diodes to deliver appropriate energy density are more advanced. Yet some Superpulsed diodes are used with extremely low average power, lacking penetration or the necessary energy density, and rendering them relatively ineffective for clinical applications.

Is laser therapy safe?

Yes, when used appropriately.  Lasers have the characteristics of intense light radiation and, when absorbed, heat. Just as you can be burned by sun exposure, or by careless application of ultrasound, mindfulness of the light and heat attributes of lasers is required, when using lasers as a therapeutic modality.

Continuous wave (CW) laser wavelengths can produce high thermal effects that must be considered. Attention to the specific patient’s condition (thermal sensitivity or insensitivity) is required.

Since CW, pulsed and superpulsed lasers produce high intensity light, often in the invisible light spectrum, the laser should never shine directly into the eye. Lasers may be used around the eyes safely, but should not enter the pupil.  Also consider the possibility of intense reflected light off of shiny surfaces in the nearby area.

Further it is recommended that laser devices not be used directly on any neoplastic tissue or recalcitrant wounds. Refrain from using laser therapy on the abdomen of pregnant patients.

Is laser therapy scientifically well documented?

There are more than 120 double-blind positive studies confirming the clinical effects of laser therapy. More than 1,000 research reports have been published. Looking at the laser therapy literature alone there are over 300 documented studies. More than 90% of these studies verify the clinical value of laser therapy.

A review of the research literature of studies that produce negative results one finds that low dose was the single most significant factor.