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Principles of Low Intensity Laser Therapy (LILT)

Low Intensity Laser Therapy (LILT) involves the application of photon energy to the tissues with the object of augmentation of healing and/or the relief of pain.

PRINCIPLES OF USE:
1) The usual wavelengths are these which penetrate most deeply due to low absorption in the principal constituent in soft tissue namely water. Typical of these are:
a) Gallium Aluminum Arsenide at around 820nm (0.82 microns) which is maximally penetrative. This modality is the most important one for treatment of pain but is also effective in healing, reaching well into connective tissue corium. Absorbed by cell wall chromophores.
b) Visible Red at 633nm (0.633 microns) Helium Neon or 660nm (0.66 microns) Diode. These wavelengths have a propensity for healing particularly epithelial tissue and for laser acupuncture. Absorbed by mitochondrial cytochromes.
2) Dosimetry is all important in determining effect and in reporting a treatment episode. It is necessary to specify:

a) Wavelength e.g.820nm

b) Incident Power of Probe e.g.200mw (a good all around value)

c) Energy Per Point e.g. 10-20 joules for myofascial pain or 2-4 joules for healing of an intractable ulcer. A 60 milliwatt probe generates 4 joules in one minute for example.

d) Energy Density ("radiant exposure" or "fluence rate") this can be calculated easily by knowing the area of the beam spot and multiplying this as a fraction of a square centimeter by the energy per point e.g. energy per point of 4 joules with the spot which is an eight of a square centimeter will result in an energy density of 4X8=32 joules per square centimeter. It should be emphasized that this is a convention which does not exactly represent the way in which photic energy is scattered in tissue as revealed by CCD camera.

A formula for more formal calculation of energy density is:
Energy density (J/CM2)= Power (w)X time (s) area(cm2)of spot

- Where the power of the probe is in milliwatts divide by 1000 to convert to watts in the formula.

e) Power Density (or "irradiance" or "fluence")

A formula for calculation of power density (w/cm2) =Power(w)

area (cm2) of spot

This can be converted to milliwatts per square centimeter by multiplying by 1000.

f) Pulsing Characteristics and Duty Cycle Declare whether constant wave or pulsed.

g) Time of Treatment This is helpful to determine rate of energy application.


3) Mechanisms of Action may be summarized as:

a) Energization of Depleted Enzymes Enzymes may be denatured or depleted in areas of inflammation by hypoxia and acidosis. Important examples are:
1) Sodium Potassium ATPASE: Vital for nerve polarisation in transmission of an action potential. Low energies (less than around 4 joules per sq.cm. at the site) tend to increase concentrations and are logical for use in nerve regeneration e.g. in facial paralysis. High energies (more than around 4 joules per sq.cm. at site) tend to decrease concentrations being indicated for pain where the object is stabilization of sensitized pain fibres-nonmyelinated C fibres for slow dull pain and lightly myelinated A delta fibres for rapid sharp pain. This is the so-called Arndt Schultz response where low energies stimulate and high energies suppress.
2) Superoxide Dysmutase (SOD). This enzyme breaks down free radicals which are a cause of pain in trigger areas in muscle in myofascial pain.
3) Transforming Growth Factor Beta Fractions. Energization will help repair and heal. There are several fractions.

b) Vascular Effects

There is no doubt that laser energy is capable of initiating new vessel formation (angiogenesis) which is an important factor in healing e.g. with soft tissue flaps. It is often suggested that LILT causes an immediate augmentation of blood flow but there is no objective evidence of this unless energies are above normal therapeutic values sufficient to cause local healing (more than 150 joules per sq.cm).

c) Immune Augmentation
It seems likely that LILT can augment local and systemic immune mechanisms particularly if these are below par. Experience with irradiation of the blood has revealed a balancing effect where low rheology values are raised and high ones brought to normal values suggesting an important role for light in homeostasis.

d) Cellular Energization
Most cells after LILT demonstrate accumulation of energy molecules in the form of ATP.
e) Overall Effect Overall, the laser energy shortens the inflammatory phase after tissue injury hastening repair and remodeling.

4) Models of Usage

a) Local application to Nociceptive Foci. e.g. trigger points in muscle. Usually constant wave, adequate power rating for penetration and positive pressure to milk out excessive tissue fluid aiding penetration.

b) Entrainment of Bioresonances LILT in pulsed mode may be geared to correspond with central bioresonances. Various frequencies are suggested (Sisken & Walker) e.g.
2Hz Nerve regeneration, neurite outgrowth
7Hz Bone growth
10Hz Ligamentous healing
15, 20, 72, Hz Decreased skin necrosis, stimulation of capillary formation and fibroblast proliferation.
c) Ligamentous Healing Low energy
d) Nerve Regeneration
e) Laser Acupuncture Over acupuncture points or known nerve outflows. These points are highly reactive responding to low energies.

f) Component of Multi-Modality Treatment Regimens When treating pain the use of several methods each working through a different substantiated mechanism are more likely to be successful then single methods (Melzak & Wall). e.g.

1) May be combined with medication such as anticonvulsant and antidepressants in chronic pain thereby reducing dosage. Cortisone steroid however may negate LILT's immune enhancement.
2) May be used with other forms of energy medicine e.g
Ultrasound
Short Wave Diathermy
Interferential Treatment
Acupuncture
Action Molecules (homeopathy)

g) Energization of Photodynamic Agents e.g. Toluidene Blue for bacterial reduction. This is an innovative which is in the experimental stage at the moment but which is likely to be increasingly important in the future in view of increasing resistance of bacteria to antibiotics.

TEXTBOOKS
Therapeutic Lasers Theory & Practice
G. David Baxter Churchill Livingstone 1994
SBN-0-443-04393-0

Energy Medicine The Scientific Basis
James L. Oschman. Churchhill Livingstone 2000
ISBN 0-443-06261-7

Low Level Laser Therapy as a Medical Treatment Entity
Pekka Pontinen Art Urpo Ltd 1992
ISBN 951-96632-0-7.

Lasers in Medicine and Dentistry: Low Intensity Laser Therapy
Editor: Z Simunovic. Vitagraf 2000
ISBN 953-6059-30-4

Low Level Laser Therapy Clinical Practice & Scientific Background
Jan Tuner & Lars Hode
Prima Books 1999. ISBN 91-630-7616-0

Teaching Module Abstract presented at the 3rd Annual Meeting of the North American Association for Laser Therapy (NAALT), Uniformed Services University for the Health Sciences, Bethesda, MD, April 4, 2003. www.naalt.org

Paul F. Bradley, M.D., D.D.S, M.S. Professor and Chairman, Oral Diagnostic Sciences. Director Head and Neck Pain, Nova Southeastern University, College of Dental Medicine. Health Professions Division 3200 South University Drive, Fort Lauderdale, FL 33328-2018

Low-Level Laser Acupuncture

Traditional Chinese Medicine (TCM) theory states that Qi, or the vital energy, is the living force behind life, all the cosmic forces in nature, and is the root of all things. Most practitioners of Oriental medicine believe that the human being is created when the Qi of Heaven and the Qi of Earth come together. Many also believe that the Qi of Heaven continues to enter the formed human body through the pineal organ in the form of light. We are perhaps starting to recognize, understand, and investigate the profound role light plays in regulating and maintaining health in the human body. Its application to acupuncture is natural.

INTRODUCTION
Just as Traditional Chinese Medicine and acupuncture are very old systems of medicine being rediscovered, so is light therapy. Heliotherapy (light therapy) was practiced by physicians in ancient cultures in Egypt, Greece, China, and India to address many conditions.1 In the 1660s, Isaac Newton separated light with a prism and discovered the visible spectrum. In the 1890s, a Danish physician, Dr Niels Finsen, pioneered light therapy. He observed that tubercular skin lesions were much more common during the long dark winter months, but rare in the summer months. In 1893, he began treating this condition, lupus vulgaris, with light. Later, he would use red light to prevent scar formation from smallpox and eventually established a light institute for the treatment of tuberculosis. So successful was his work in treating skin tuberculosis with ultraviolet light that he was awarded the Nobel prize in 1903. This was the first recognized therapeutic application of an artificial light source.2

In the United States, Dr Dinsha Ghadiali, an American who emigrated from India in the 1800s, also did extensive work with photo therapy, but his alternative approaches to healing were met with resistance and most of his work was destroyed.3 Low-level lasers are still considered investigational in the United States. The US Food and Drug Administration (FDA) has approved some low-level lasers for limited applications. It has been shown that low-level lasers can be effective, but their optimal treatment parameters are not known.

BASIC SCIENCE
Works of the above-mentioned innovators and others provide us with sufficient empirical evidence of the value of light in medicine. The scientific evidence for this rests in quantum physics and the color theory, the photoelectric effect first discovered by Hertz, and the theory of light elucidated by Albert Einstein. According to the photoelectric effect, when light strikes any material substance, electrons are discharged, creating a current. Simply, light interacts with matter as the energy of the light is transferred to the electrons. In 1905, Einstein offered an explanation for this phenomenon with his Corpuscular Theory of Light, for which he was awarded a Nobel Prize.

Einstein proposed that light is composed of corpuscular units called photons. He further claimed that a photon is the smallest unit of light and has a dual nature, being both a particle and a wave at the same time. A photon travels at the speed of light and its energy is related to the frequency of radiation. The energy of the photon is transferred to the electrons when it collides with any material substance. The shorter the waves of light, the greater the energy is transferred to the electron (Figure 1). The intensity of the light determines how many photons strike given surface and how many electrons are, thus, affected. The higher the intensity, the greater the number of photons and therefore, the greater the amount of energy transferred to the electrons. Hence the physics of lasers were first imagined by Einstein.2,4

Color is frequency within the visible spectrum of light. It is composed of a small band of the total electromagnetic spectrum, from violet at 400 nm (higher-energy photon) through red at 700 nm (lower-energy photon) (Figure 2). Beyond violet, in increasingly shorter wavelengths, are ultraviolet light, x-rays, and gamma radiation which contain tremendous amounts of energy. Infrared and radio waves are longer wavelengths outside the red end and less energetics. Each color of the spectrum is composed of a band of frequencies. Therapeutic application of light to the body is accomplished by applying a single monochromatic wavelength within that band.2,4-7

In the 1960s, Theodore Maiman, a physicist, constructed the first laser at Hughes Aircraft Research Laboratories in Malibu, California. The early 1960s saw the development of numerous lasers and numerous new applications in industry and medicine. Many of these new medical applications were in surgery and involved powerful instruments with outputs in the tens-to-hundreds of watts. Surgeons noticed faster healing times and less scarring when doing procedures with lasers than when using the standard scalpel. This was later found to be the result of biostimulation.4

Russian researchers at the Institute for Clinical and Experimental Medicine have shown that light applied to the human skin penetrates the body between 2 and 30 mm, depending on the color frequency. The researchers also found that only certain areas of the body were able to transfer light beneath the surface, and these areas corresponded to acupuncture points. Furthermore, the light was conducted within the body along the acupuncture meridians. It appears that the meridians are a light transferral system within the body somewhat like optical fiber.8

Tina Karu, PhD, of the Laser Technology Center in Russia and affiliated with the University of California at Berkley, has researched the effects of light on the cell since the 1980s. She found there are photo receptors at the molecular level that, when triggered, activate a number of biological reactions such as DNA/RNA synthesis, increased cAMP levels, protein and collagen synthesis, and cellular proliferation. The result is rapid regeneration, normalization, and healing of damaged cellular tissue. Thus, light is a trigger for the rearrangement of cellular metabolism.1,2,4,5,9

In 1966, Endre Mester, a physician in Hungary, performed a series of experiments that showed the biostimulatory effect of visible red and infrared laser light at low intensity. He published his findings in an obscure Hungarian medical journal, which may explain why the benefits of low-level lasers were appreciated in the Eastern bloc long before they were recognized in the West. In the United States, Margaret Naesser, PhD, research professor and acupuncturist at Boston University School of Medicine, conducted research using low-level laser acupuncture with positive results for the treatment of paralysis in patients following stroke and in carpal tunnel syndrome.4

WHAT IS A LASER?
A laser (light amplification by stimulated emission of radiation) is an amplifier of light. It is a specialized environment that will support and sustain stimulated emission. There are 2 properties of laser light that separates it from incandescent light (such as that from a light
bulb).2,4,10

Monochromatic. A laser emits light at a specific wavelength, pure light, rather than over the wide spectral distribution of most light sources. It has a very narrow band width.

Coherent. Laser light is extremely well organized and synchronous (Figure 3). The photons emitted from a laser have been compared to a troop of soldiers marching in precise order.

Two of the most common misconceptions about lasers is that 1) all lasers are high powered, and 2) their beams are always parallel. Conversely, low-level lasers are most often designed with divergent beams as a safety precaution, and they operate at very low levels of power (0.05 to 0.5 W).2,4

Figure 1. Relationship of wavelength to energy


Figure 2. The electromagnetic spectrum




Principles of Use
Low-level laser acupuncture involves the application of photic energy to acupuncture points/tissues with the objective of augmentation of the normal healing process and/or pain relief. The usual wavelengths of lasers that are most commonly used in acupuncture are those that penetrate most deeply due to low absorption in the principal constituent in soft tissues, water.1 Except for the helium-neon laser, currently all therapeutic/low-level lasers use a diode.

Helium-Neon Laser (632.8 nm)
Helium-neon gas mixture. Visible red light. Relatively shallow depth of penetration. Very useful for laser acupuncture, superficial applications, and wound healing. Absorbed by mitochondrial cytochromes. Large, fragile, and expensive instrument (Figure 4).

Indium-Gallium-Aluminum-Phosphorus Laser (633-635 nm)
Now replacing helium-neon lasers. Visible red light, smaller and portable, inexpensive; higher power than the helium-neon, more durable. Same applications as helium-neon (Figure 4).

Gallium-Aluminum-Arsenide Laser (780-890 nm)
Deeper penetration. Near infrared, invisible light. Many applications, inexpensive, very useful for the treatment of pain, but also effective in healing. Most popular therapeutic laser. Valuable to reach very deep acupuncture points or deep Ah Shi points (Figure 4).

Gallium-Arsenide Laser (904 nm)
Greatest depth of penetration, deeper than gallium-aluminum-arsenide. This is due to a much longer wavelength and because they are pulsed, forcing the laser light deep into the tissues. Useful for reaching deep acupuncture points and for the treatment of pain. Continuous wave lasers are now also available (Figure 4).

Mechanism of Action
Energization of depleted enzymes. This may be denatured or depleted in areas of inflammation by hypoxia and acidosis. Examples are:

Sodium Potassium ATPase. Essential for nerve polarization in transmission of an action potential. Low-laser energies (<4 J/cm2 at a given site) tend to increase its concentration and are therefore recommended in cases where nerve regeneration or stimulation is desirable (e.g., Bell's palsy or facial paralysis).1 (The biostimulatory effects of low-level laser are governed by the Arndt-Schulz Law in which low energies stimulate and high energies suppress.1,2,4)

High-laser energies (>4 J/cm2), in contrast, tend to decrease its concentration, therefore being indicated for pain where the object is stabilization of sensitized pain fibers.1

Superoxide Dysmutase. This enzyme breaks down free radicals, which are a cause of pain in trigger areas in myofascial pain.

Transforming Growth Factor (b Fraction). Energization will help accelerate the repair and healing process.1

Vascular Effects. Evidence exists that laser energy is capable of initiating new vessel formation, which is an important factor in the healing process.1,5

Cellular Energization
Cells, after exposure to low-level laser, demonstrate accumulation of energy molecules in the form of ATP.1,5

Overall Effect
Low-level laser photic energy shortens the inflammatory phase, accelerating the repair process, and remodeling after tissue injury. In addition, increased plasma concentrations of certain types of prostaglandins, enkephalins, and endorphins have all been identified and most likely play a major role in the mechanisms associated with pain attenuation.1,5,11

Safety
Low-level lasers are very safe; however, there is a potential for damage to the eye. The laser beam, if directed through the lens of the eye, could damage the retina. Yet in more than 30 years of research and clinical practice, an event of this type has never been reported. Protective goggles that filter out the specific wavelength of the laser light should be worn by the patient and acupuncturist/physician during a therapy session.

To safely operate a laser, the practitioner must thoroughly understand the nature of the equipment.2,4,6,10 Certain technical parameters exist that one must first comprehend. These parameters are the power (for low-level lasers, this is expressed in milliwatts), wavelength, the characteristics of the laser beam (its optics; such as divergence, convergence, or parallel nature of the beam). All these influence the level of risk. Obviously, a high-power laser is riskier than a lower-power one. An infrared laser is riskier to use than a visible, red light laser with the same power and beam characteristics because the light is invisible and does not promote a blink response.2,4,6,10

INDICATIONS
The following is a partial list of conditions that have shown promising results with laser acupuncture. Laser acupuncture is painless and may be offered to patients with needlephobia and to children.1,2,4,10-18

Acute/chronic pain


TMJ dysfunction

Paresthesias


Cervical/lumbar spine syndromes

Neuralgias


Dermatoses

Allergic rhinitis/sinusitis


Asthma

Frozen shoulder


Phantom pain

Arthritis/arthrosis


Fibromyalgia

Bursitis, tendonitis


Nerve regeneration

Carpal tunnel syndrome


Wound healing

In addition, most lasers may be used in all instances for which moxibustion is indicated. There is no reducing or tonifying technique when performing laser acupuncture. Low-level lasers when used in pulsed mode have significant effects that may correspond with central bioresonances. The following frequencies are suggested from prior research studies.1,2,4,10,17,18

2 Hz


Nerve regeneration, neurite outgrowth

7 Hz


Bone growth

3-20 Hz


Pain

700-2500 Hz


Stimulatory effect

>2500 Hz


Inflammation, edema

>5000 Hz




Laser acupuncture may be combined with regular needle acupuncture at the same time with other forms of energy medicine (e.g., homeopathy, Chinese herbs, etc), and with medications such as anticonvulsants and antidepressants in chronic pain management, thereby reducing their dosage.

DISCUSSION
No doubt, the FDA will continue to approve the use of lasers for a variety of conditions (recently, a laser company in the United States received approval for the treatment of carpal tunnel syndrome). There are FDA guidelines that govern the use of low-level lasers as an investigational device, as well as state regulations. The FDA classifies low-level lasers as class IIIB non-significant risk devices.

CONCLUSION
Low-level lasers are used extensively in Europe and Asia for many applications, including acupuncture. Low-level lasers may be an effective modality in battling many situations. More research is needed to establish ideal treatment parameters for specific conditions.

Figure 3. Comparison of laser and other light sources


Figure 4. Relative depth of various lasers commonly used in acupuncture




REFERENCES

1. Bradley PF. Laser basics: principles of low intensity laser therapy (LILT). Presented at: Third Annual Conference of the North American Association for Laser Therapy.
2. Tuner J, Hode L. Laser Therapy: Clinical Practice and Scientific Background. Gransgesberg, Sweden: Prima Books; 2002.
3. Dinsha D. Let There Be Light. Malaga, NJ: Dinsha Health Society; 1996.
4. Blahnik JA, Rindge DW. Laser Therapy: A Clinical Manual. Melbourne, FL: Healing Light Seminars Inc; 2003.
5. Karu T. The Science of Low Power Laser Therapy. Amsterdan, the Netherlands: Gordon and Beach Science Publishers; 1998.
6. Oshiro T, Calderhead RG. Low Level Laser Therapy: A Practical Introduction. Chichester, England: John Wiley & Sons Ltd; 1988.
7. Mandel P. Practical Compendium of Colorpuncture. Bruchsal, Germany: Ditton Energetik; 1986.
8. Pankratov S. Meridians Conduct Light. Germany: Raum & Zeit; 1991.
9. axter DG. Therapeutic Lasers: Theory and Practice. New York, NY: Churchill Livingstone; 1994.
10. Naesser M. Laser Acupuncture: An Introductory Textbook for Treatment of Pain, Paralysis, Spasticity and Other Disorders (Clinical and Research Uses of Laser Acupuncture From Around the World). Boston, MA; Boston Chinese Medicine; 1994.
11. Moore K. Lasers and Pain Treatment. Cinixeperience: Laser Partner. Official paper of the Czech Society for the Use of Laser in Medicine. February 26, 2004.
12. Braverman B, et al. Effects of helium-neon and infrared laser irradiation on wound healing in rabbits. Lasers Surg Med. 1989;9:50.
13. Rochkind S, et al. Systemic effects of helium-neon laser irradiation on the peripheral and central nervous system, cutaneous wound and burns. Lasers Surg Med. 1982;26:12.
14. Ariaksinen O, et al. Effects of helium-neon laser irradiation on the trigger points of patients with chronic muscle tension in the neck. Scand J Acupuncture Electrother. 1989;3:63-65.
15. Ponnuradai RN, et al. Hypoalgesic effect of laser photobiostimulation shown by rat tail flick test. Int J Acupunct Electrother Res. 1987;12:93-100.
16. Mokhtar B, et al. A double blind placebo controlled investigation of the hypoalgesic effect of low intensity laser irradiation of the cervical roots using experimental ischemic pain. Presented at: ILTA Congress; London, England; 1992. Abstracts :61.
17. Mokhtar B et al. The possible significance of pulse repetition rate in laser mediated analgesia: a double blind placebo controlled investigation using experimental ischemic pain. Presented at: ILTA Congress; London, England; 1992. Abstracts :62.
18. Kucerova H, et al. Modulatory frequency of lasers in connection to laser beam therapeutic effect. Proc SPIE. 1998;3248L:191-195. Lasers in Dentistry IV.
Author: Jose T. Vargas is a Board-certified acupuncturist, specializing in laser acupuncture. He is a Senior Physician Assistant for the Department of Medicine at Montefiore Medical Center of the Albert Einstein College of Medicine in New York City, and a faculty member at New York College of Traditional Chinese Medicine in Mineola, NY.
Jose T. Vargas, MSc, LAc, PA-C*

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