Understanding Lasers and How They Work

Therapeutic Laser for Health and Healing

The word LASER is an acronym for Light Amplification by Stimulated Emission of Radiation, a term coined in the 1960s to describe a new class of light-emitting devices capable of producing highly focused, coherent beams of energy. While early laser research focused on industrial and surgical applications, Dr. Endre Mester, a Hungarian physician, is credited with discovering the biostimulatory effects of laser therapy. In 1967, Mester conducted an experiment using a ruby laser to study its effects on cancerous tumors in rats. While the laser failed to produce the anticipated tumor suppression, Mester observed something unexpected—the laser-treated wounds healed faster, and hair regrowth was accelerated compared to the control group. This accidental discovery laid the foundation for what is now known as photobiomodulation therapy (PBMT), a field dedicated to using specific wavelengths of light to enhance cellular function, promote healing, and reduce pain.

What is a Class IV Laser?

A Class IV laser is a high-powered laser device classified by the FDA and the IEC (International Electrotechnical Commission) based on its output power. Any laser exceeding 500 milliwatts (mW) is categorized as Class IV and is used in medical, therapeutic, and surgical applications.

Unlike surgical lasers, which cut or burn tissue, Class IV therapeutic lasers are specifically designed to stimulate cellular function, promote healing, and reduce pain without causing damage. This makes them a powerful alternative to low-power lasers (Class IIIb) and light-emitting diodes (LEDs) for therapeutic use.

Therapeutic Lasers vs. Surgical Lasers: Understanding the Difference

Class IV lasers can be divided into two main categories:

Surgical (Cutting/Burning) Lasers:

Used in procedures requiring tissue cutting, cauterization, or vaporization.
Operate at very high power densities designed to destroy or remove tissue through thermal effects.
Common in dermatology, ophthalmology, and surgical applications such as LASIK eye surgery and tumor removal.

Therapeutic (Photobiomodulation) Lasers:

Used to stimulate cellular function without generating destructive heat.
Deliver controlled doses of red and near-infrared (NIR) light to penetrate deep into tissues, enhance healing, and modulate inflammation.
Do not cut, burn, or damage tissue and are optimized for biostimulation rather than ablation.

This distinction is critical, as some misconceptions exist regarding the safety of Class IV lasers. Many assume they cause damage similar to surgical lasers, but in reality, Class IV therapeutic lasers are designed for healing and cellular repair rather than tissue destruction.

Cold Lasers, Soft Lasers, and Biostimulation

The term “cold laser” is commonly used to describe low-level laser therapy (LLLT) or photobiomodulation therapy (PBMT). These lasers do not produce significant heat and do not cause tissue damage, making them distinct from high-intensity surgical lasers.

Other frequently used terms include:

Soft Laser – A historical term referring to non-thermal, non-ablative laser treatments for pain relief and healing.
Biostimulation (Biostim) Laser – Refers to the process where laser light stimulates biological activity, improving cellular function, circulation, and ATP production.

While cold lasers typically refer to low-power Class IIIb lasers, Class IV therapeutic lasers can also be used safely for biostimulation when applied correctly. The advantage of a Class IV therapeutic laser over a Class IIIb or LED device is its deeper tissue penetration and more efficient energy delivery, allowing for faster and more effective treatments.

Why Therapeutic Lasers are Superior to LEDs

While both lasers and LEDs are used in photobiomodulation therapy, lasers offer significant advantages due to their unique optical properties:

1. Collimation (Laser Light Stays in a Tight Beam)

Lasers produce a collimated beam, meaning the light waves travel in parallel with minimal dispersion.
This allows more energy to penetrate deep into tissues, reaching structures that LEDs cannot effectively target such as the ovaries.
LEDs emit divergent light, meaning energy spreads out and loses intensity before reaching deeper tissues.

2. Coherence (Organized Light Waves for Higher Precision)

Laser light is coherent, meaning its waves move in sync, amplifying their biological effects.
Coherent light has been shown to enhance cellular response more effectively than incoherent light from LEDs.
LED light is non-coherent, scattering in multiple directions, reducing its ability to stimulate cellular activity as efficiently as a laser.

3. Reduced Scattering and Increased Depth of Penetration

Laser light penetrates tissue in a more controlled and predictable manner, delivering energy directly to targeted cells.
LEDs scatter light extensively, leading to greater superficial absorption and reduced penetration into deeper tissues.
This makes Class IV lasers more effective for treating deep musculoskeletal conditions, nerve injuries, and joint pain, whereas LEDs are better suited for surface-level treatments.

4. Power Density and Treatment Efficiency

Class IV lasers provide a higher power output, allowing for shorter treatment times with greater effectiveness.
LEDs require longer exposure times due to their lower power density and scattered energy distribution.

While LED therapy has its place in surface-level applications, Class IV therapeutic lasers offer superior penetration, precision, and efficiency, making them the preferred choice for deep tissue repair, pain management, and cellular regeneration.

How Class IV Therapeutic Lasers Work

Class IV therapeutic lasers work through photobiomodulation (PBM), a process where light energy is absorbed by cellular structures, particularly the mitochondria.

Key Biological Mechanisms of PBMT

Increases ATP Production: Laser energy stimulates cytochrome c oxidase (CCO) in mitochondria, leading to increased cellular energy (ATP) and faster tissue repair.
Enhances Circulation and Oxygenation: PBMT promotes vasodilation, improving blood flow and nutrient delivery to injured or inflamed tissues.
Reduces Inflammation: PBMT modulates inflammatory cytokines, helping reduce swelling and chronic inflammation.
Modulates Pain Signals: Laser therapy reduces the excitability of pain receptors and increases the release of natural pain-relieving endorphins.
Accelerates Wound Healing and Tissue Regeneration: PBM stimulates fibroblast activity and collagen production, improving wound healing and reducing scar formation.

Safety of Class IV Therapeutic Lasers

Class IV lasers are safe when used correctly by trained professionals. Despite their higher power output compared to Class 3b lasers, they do not cause tissue damage when applied within therapeutic parameters.

Key safety considerations include:

Proper Dosing: Class IV lasers allow for adjustable power levels, ensuring treatments remain therapeutic, not ablative.
Eye Protection: As with all medical lasers, protective eyewear is required to prevent accidental exposure to the eyes.
Controlled Application: Laser operators follow protocols to ensure the correct wavelength, power, and duration are applied for each condition.

Why Choose a Class IV Therapeutic Laser?

Compared to low-power Class IIIb lasers and LEDs, Class IV lasers provide:

Deeper Tissue Penetration – More effective for musculoskeletal conditions, nerve injuries, and deep-tissue healing.
Faster Treatment Times – Higher energy output reduces session duration while maintaining safety.
Versatile Applications – Suitable for pain management, inflammation reduction, injury recovery, and post-surgical healing.

Class IV therapeutic lasers provide a safe, efficient, and scientifically validated method for enhancing healing and reducing pain, making them an excellent choice for medical, holistic, chiropractic,fertility, sports rehabilitation, and pain management clinics.