What is LASER?
stands for Light Amplification by Stimulated
Emission by Radiation.
What is LLLT?
Level Laser Therapy (LLLT) is
the new internationally accepted term for
biostimulation with low energy lasers in order to
achieve therapeutic desired effects.
Light or photon energy with the unique property of
being able to penetrate up to two inches below the
skin surface causing an increase in cellular
metabolism with no tissue damage whatsoever.
Low level laser therapy, sometimes also referred to
as cold laser therapy is quickly becoming the first
line of attack in pain control and tissue healing in
Laser treatment in which energy output is low enough
so that the temperature of the treated tissue does
not rise above 98.6 F (normal body temperature). Low
level laser therapy is safe, painless, and
non-invasive and the results are often immediate and
What is LILT, LPLT,
therapeutic laser, soft laser, MID laser….etc.?
the literature LILT (Low Intensity Laser
Therapy) and LPLT (Low Power Laser Therapy)
is also frequently used.
Regarding the laser instrument, chose to use
the term "therapeutic laser" rather than "low level
laser" or "low power laser", since high level lasers
are also used for laser therapy.
The term "soft laser" was originally used to
differentiate therapeutic lasers from "hard lasers",
i.e. surgical lasers.
MID Laser; Medical Laser:
Several different designations then emerged, such as
"MID laser" and "medical laser".
has been proposed with the disadvantage that one can
also give inhibiting doses.
and Photo-biomodulation laser are other
Thus, it is obvious that the question of
nomenclature is far from solved.
This is because there is a lack of full agreement
internationally, and the names proposed thus far
have been rather unwieldy. Feel free to forget them,
but remember laser therapy or LLLT until agreement
is reached on something else.
Who are the pioneers
of low level laser therapy?
The first systemic scientific
research on the biological effects of low level
laser was conducted by the late Professor Endre
Mester of the Semmelweis Medical University in
Budapest, Hungary, 1966.
Is laser therapy scientifically well
has been in active and beneficial use in Europe for
nearly 30 years. There are more than 100
double blind positive studies confirming the
clinical effect of LLLT. Over 2,500 clinical studies
and published research reports have shown the
effectiveness of LLLT for a variety of health
issues. Looking at the limited LLLT dental
literature alone (370 studies), more than 90%
of these studies do verify the clinical value of
has been a staple in veterinary practices for
In the past 6 years, professional sports teams have
begun utilizing LLLT.
Where do I find such documentation?
book of authors Tunér and Hode “Laser Therapy -
Clinical Practice and Scientific Background" is a
reference guide as well as a wealth of laser therapy
knowledge. The book contains 600 pages, multicolored
and loaded with new information about the clinical
and scientific aspects of laser therapy. Among other
things there are about 1400 references.
But I have heard that there are
dozens of studies failing to find any effect of LLLT?
That is true. But you can not just
take a laser and irradiate for any length of time
and using any technique. A closer look at the
majority of the negative studies will reveal serious
flaw. Look for link under Laser literature and read
some examples. But LLLT will naturally not work on
anything. Competent research certainly has failed to
demonstrate effect in several indications. However,
as with any treatment, it is a matter of dosage,
diagnosis, treatment technique and individual
What other conditions does the Low
Level Laser help treat?
Low Level Laser is being used to
treat a variety of painful and inflamed conditions
of the soft tissues and joints.
Joint Pain in knees, hands, ankles, and hips
Arthritis, Osteoarthritis, Rheumatoid Arthritis
Chronic neck, back, and shoulder pain
Carpal Tunnel Syndrome
Rotator Cuff Injury
Tennis Elbow and Golfer’s elbow
Is Low Level Laser Therapy safe and
is there any side effect?
In the past 4 years, the FDA has ruled that LLLT
(Low Level Laser Therapy) is safe and the only
contraindication (warning) is not to use it
directly in the eyes.
For the past 30 years the technology of Low Level
Laser Therapy (LLLT) has been formally accepted in
many parts of the world such as Europe, Scandinavia,
Russia and Japan. In all this time there have been
no recorded long-term adverse effects from its use.
It is considered to be non-invasive, painless and
The question is often asked "If it's a laser aren't
they used in surgical operations, to cauterize
tissue?" The answer is "Yes" - Hot Lasers are able
to cauterize (cut) tissue. However, the ones we use
are "Low Level Laser" with designed parameters that
make it impossible to damage even one cell in the
body. Our lasers stimulate and energize the cells.
Industry has been using laser diodes for years in
such applications as bar code readers, CD players,
DVD players, laser printers and pointers. The FDA
has listed bio-stimulation lasers as non-significant
risk (NSR) devices.
The low level lasers shown here have received UL and
CE approval for safety.
How does it work?
All light has an effect on the cells of the human
body. What that effect is shall be determined by the
wavelengths of light applied. The low level laser
produces a beam of light that has a specific
wavelength and frequency. When the light of the
laser is applied around the tissue, the
electromagnetic energy is converted to chemical
energy within each cell which sets in motion a chain
of chemical reactions allowing the healing process
to begin. This chemical reaction in the cell allows
several things to occur.
Stimulates Healing and Repair of Tissue
Increases Tissue Strength
stimulating cells to produce their own endorphins, a
natural pain killer. Pain results from trauma,
cellular disruption, malfunction, or less than
optimal cellular function. Healing and pain relief
come with cellular normalization. Photons enable
cells to perform optimally by stimulating them to
initiate bio-chemical reactions which produce
enzymes and ATP (usable energy).
by suppressing inflammatory enzymes and enhancing
the release of anti-inflammatory enzymes as much as
by stimulating lymphatic drainage
Promotes Faster Wound Healing:
by stimulating cells to increase the production of
two major healing enzymes by as much as 75%,
enhances lymphatic drainage thereby increasing
circulation and speeding healing.
Increase Bone Repair Speed:
by stimulating fibroblastic and osteoblastic
Stimulates Nerve Function
Promotes Cellular Oxygenation/Detoxification
Release Tight Muscles and Muscle Spasms:
(both smooth and striated) that help create chronic
pain, join problems and decreased mobility.
Enhance the Immune System:
by increasing the number of "killer" cells by
Re-energize Cell Membranes:
to allow transport of essential nutrients across
cell walls (nutrients will not cross an injured or
sick cell wall, thus slowing healing) allowing a
healthy new cell to grow.
Is this a temporary
fix to my problem?
The good news is for
most patients that have completed our Low level
Laser Knee Program the results from the treatments
have been sustainable. While some patients get
immediate results, others usually require 6-12
treatments before there is a lasting effect. Since
each person’s condition varies in severity the
doctor will determine after reviewing your condition
if laser treatments may benefit you.
Which lasers can be used in medicine?
Examples of lasers that can be used
Laser name Wavelength Pulsed Use in medicine or
Crystalline laser medium:
Ruby 694 nm p holograms, tattoo coagulation
Nd: YAG 1 064 nm p coagulation
Ho: YAG 2 130 nm p surgery, root canal
Er: YAG 2 940 nm p surgery, dental drill
KTP/532 532 nm p/c dermatology
Alexandrite 720-800 nm p bone cutting
GaAs 904 nm p biostimulation
GaAlAs 780-820-870 nm c biostimulation, surgery
InGaAlP 630-685 nm c biostimulation
Dye laser (tunable) p kidney stones
Rhoda mine: 560-650 nm c/p PDT, dermatology,
HeNe 633, 3 390 nm c biostimulation
Argon 350-514 nm c dermatology, eye
CO2 10 600 nm c/p dermatology, surgery
Exciter 193, 248, 308 nm p eye, vascular surgery
Copper vapor 578 nm c/p dermatology
There are many other types, but those mentioned
above are the most common.
How come some LLLT
equipment has power in watts and some only in milliwatts?
This applies to GaAs lasers. When a
GaAs laser works in a pulsed fashion, the laser
light power varies between the peak pulse output
power and zero. Then usually the laser's average
power output is of importance, especially in terms
of dosage calculation. The peak pulse power value is
of some relevance for the maximum penetration depth
of the light. Some manufacturers specify only the
peak pulse output in their technical specifications.
"70 millwatt peak pulse output" naturally seems more
impressive than 35 milliwatts average output! Rule
of thumb is: Take the "watt peak pulse" figure,
divide by 2, and you have the average output in mW.
This rule of thumb is not valid for GaAs-lasers as
these lasers are super pulsed (extremely low duty
What are the most
common laser types in LLLT?
Helium-Neon (HeNe) - visible, red
AlGaInP- visible, red
Gallium-Arsenide (GaAs) - invisible, infrared
Gallium-Aluminum-Arsenide (GaAlAs) - invisible,
What is the
difference between visible red lasers and invisible,
Visible red lasers penetrate the skin
poorly, therefore are more suitable for superficial
(skin and mucosal) lesions, superficial muscle and
connective tissue injuries.
Infrared lasers, such as the HB-750 Laser penetrate
deeper and are suitable for both superficial and
Which type of laser
is best suited to which job?
There are three main types of laser
on the market: HeNe (now being gradually replaced by
the InGaAlP laser), GaAs and GaAlAs. They can be
installed in separate instruments or combined in the
The HeNe laser or InGaAlP laser has been used a
great deal in dentistry in particular, as it was the
first laser available. The HeNe laser has been used
for wound healing for more than 30 years. One
advantage is the documented beneficial effect on
mucous membrane and skin (the types of problem it is
best suited to), and the absence of risk of injury
to the eyes. A Japanese researcher has even treated
calves with kerato conjunctivitis with excellent
results, that is, irradiation of the eye through the
eyelid. Because HeNe light is visible, the eye's
blink reflex protects it.
Normal HeNe output for dental use is 3-10 mW,
although apparatus with up to 60 mW is available. An
optimal dosage when using a HeNe laser for wound
healing is 1-4 J/cm2 around the edge of the wound,
and approximately 0.5 J/cm2 in the open wound. HeNe
lasers are used to treat skin wounds, wounds to
mucous membrane, herpes simplex, herpes zoster
(shingles), gingivitis, pains in skin and mucous
membrane, conjunctivitis, etc.
It should be noted that HeNe fibers couldn't’t be
sterilized in an autoclave. The alternative is to
use alcohol to clean the tip, or to cover it with
cling-film or a thermometer sleeve.
The GaAs laser is excellent for the treatment of
pain and inflammations (even deep-lying ones), and
is less suited to the treatment of wounds and mucous
membrane. Very low dosages should be administered to
mucous membrane! Most GaAs equipment is intended for
extra oral use, but there are special lasers adapted
for oral use.
A GaAs laser needs an integral output meter that
shows that there is a beam and its strength in
milliwatts - this is necessary because the light
this type of laser emits is invisible. Protective
glasses for the patient may be appropriate in view
of the invisible nature of the light.
In older systems the power output of conventional
apparatus follows pulsation. This means that a GaAs
laser with an average output of 10 mW when pulsing
at 10,000 Hz only produces 1 mW when pulsed at 1,000
Hz and at 100 Hz only 0.1 mW. If you therefore want
to administer treatment at low frequencies around
e.g. 20 Hz (for the treatment of pain), the output
power is, clinically speaking, unusable. However,
there are GaAs lasers with "Power Pulse", which
means that the power output is held constant at all
pulse frequencies. This would be of interest to a
physiotherapist, for example, when one considers
that the GaAs laser has the deepest penetration of
the common therapeutic lasers. Large doses can be
administered to deep-lying tissue over a short
period of time. A GaAs multi-probe can also shorten
treatment times for conditions involving larger
The GaAs laser is, like GaAlAs and InGaAlP lasers, a
semiconductor laser. A purely practical advantage of
this type of laser is that the laser diode is
located in the hand-held probe. This means that
there is no sensitive fiber-optic light conductor,
which runs from the laser apparatus to the probe,
but just a normal, cheap, robust electric cable.
Optimum treatment dosages with GaAs lasers are lower
than with HeNe lasers. The GaAs laser is most
effective in the treatment of pain, inflammations
and functional disorders in muscles, tendons and
joints (e.g. epicondylitis, tendonitis and
Myofascial pain, gonarthrosis, etc.), and for
deep-lying disorders in general. As mentioned above,
GaAs is not thought to be as effective on wounds and
other superficial problems as the HeNe laser T (InGaAlP
laser) and GaAlAs laser. GaAs can, nevertheless, be
used successfully on wounds in combination with HeNe
or InGaAlP, but the dosages should be very low -
under 0.1 J/cm2.The GaAlAs laser has become
increasingly popular. GaAlAs lasers have appeared on
the market with an impressive output of over 2 W.
There are several types of GaAlAs-lasers. The most
well documented type emits a continuous, invisible
or barely visible light with the wavelength 820 nm.
This laser assume an intermediate position as
compared to the two other laser types, often proving
effective on such skin conditions as leg ulcers but
also, at least to some extent, on the problems of
muscles, tendons and joints.
Many GaAlAs lasers have well-designed, exchangeable,
sterilisable intraoral probes. Output meters are
essential because the light from this type of laser
is largely invisible.
Can carbon dioxide
lasers be used for LLLT?
Therapeutic laser treatment with carbon dioxide
lasers has become more and more popular, sometimes
called EDL-laser (emitted defocused laser). This
does not require instruments expressly designed for
that purpose. Practically any carbon dioxide laser
can be used as long as the beam can be spread out
over an appropriate area, and as long as the power
can be regulated to avoid burning. This can always
be achieved with an additional lens of germanium or
zinc selenide, if it cannot be done with the
standard accessories accompanying the apparatus.
It is interesting to note that the CO2 wavelength
cannot penetrate tissue but for a fraction of an mm
(unless focused to burn). Still, it does have
biostimulative properties. So the effect most likely
depends on transmitter substances from superficial
blood vessels. Conventional LLLT wavelengths combine
this effect with "direct hits" in the deeper lying
How deep into the
tissue can a laser penetrate?
The depth of penetration of laser
light depends on the light's wavelength, on whether
the laser is super-pulsed, and on the power output,
but also on the technical design of the apparatus
and the treatment technique used. A laser designed
for the treatment of humans is rarely suitable for
treating animals with fur. There are, in fact,
lasers specially made for this purpose. The special
design feature here is that the laser diode(s)
obtrude from the treatment probe rather like the
teeth on a comb. By delving between the animal's
hairs, the laser diode's glass surface comes in
contact with the skin and all the light from the
laser is "forced" into the tissue. A factor of
importance here is the compressive removal of blood
in the target tissue. When you press lightly with a
laser probe against skin, the blood flows to the
sides, so that the tissue right in front of the
probe (and some distance into the tissue) is fairly
empty of blood. As the hemoglobin in the blood is
responsible for most of the absorption, this
mechanical removal of blood greatly increases the
depth of penetration of the laser light.
It is of no importance whether the light from a
laser probe, held in contact with skin is a parallel
beam or not.
There is no exact limit with respect to the
penetration of the light. The light gets weaker and
weaker the further from the surface it penetrates.
There is, however, a limit at which the light
intensity is so low that no biological effect of the
light can be registered. This limit, where the
effect ceases, is called the greatest active depth.
In addition to the factors mentioned above, this
depth is also contingent on tissue type,
pigmentation, and dirt on the skin. It is worth
noting that laser light can even penetrate bone (as
well as it can penetrate muscle tissue). Fat tissue
is more transparent than muscle tissue.
For example: a HeNe laser with a power output of 3.5
mW has a greatest active depth of 6-8 mm depending
on the type of tissue involved. A HeNe laser with an
output of 7 mW has a greatest active depth of 8-10
mm. A GaAlAs probe of some strength has a
penetration of 35 mm with a 55 mm lateral spread. A
GaAs laser has a greatest active depth of between 20
and 30 mm (sometimes down to 40-50 mm), depending on
its peak pulse output (around a thousand times
greater than its average power output). If you are
working in direct contact with the skin, and press
the probe against the skin, then the greatest active
depth will be achieved.
Can LLLT cause
The answer is no. No mutational
effects have been observed resulting from light with
wavelengths in the red or infrared range and of
doses used within LLLT. But what happens if I treat
someone who has cancer and is unaware of it? Can the
cancer's growth be stimulated? The effects of LLLT
on cancer cells in vitro have been studied, and it
was observed that they could be stimulated by laser
light. However, with respect to a cancer in vivo,
the situation is rather different. Experiments on
rats have shown that small tumors treated with LLLT
can recede and completely disappear, although laser
treatment had no effect on tumors over a certain
size. It is probably the local immune system, which
is stimulated more than the tumor.
The situation is the same for bacteria and virus in
culture. These are stimulated by laser light in
certain doses, while a bacterial or viral infection
is cured much quicker after the treatment with LLLT.
What happens if I use
a too high dose?
You will have a biosuppressive
effect. At least if you try to heal of a wound or
treat for hair loss, then it will take longer time
than normally. Very high doses on healthy tissues
will not damage them.
Are there any counter
should not treat cancer, for legal reasons. Pregnant
women are not a counter indication, if used with
common sense. Pace makers are electronically, do not
respond to light. Epilepsy may be a counter
indication. The most valid counter indication is
lack of medical training.
Will I feel anything?
No. Low level lasers do not generate
perceivable heat. Therefore, when the laser contacts
the skin the patient experiences no burning as a
result of the laser. Most people feel nothing at all
while a few may feel a slight tingling during the
Does LLLT cause a
heating of the tissue?
Due to increased microcirculation
there is usually an increase of 0.5~1 centigrade
locally. The biological effects have nothing to do
with the heat. Our patented taped-laser module plays
a roll of laser beam reflection shield, makes more
microcirculation. Therefore, an increase of 2~3
centigrade in the attached part is normal. Other
GaAlAs lasers in the 300-500 mW or higher range will
cause a noticeable heat sensation, particularly in
hairy areas and on sensitive tissues such as lips.
Does it have to be a laser? Why not
use monochromatic non-coherent /LED/other types of
Light emitted from a laser diode is
monochromatic (having only one wavelength), parallel
and coherent (having waves with similar direction,
amplitude, and phase). These qualities make laser
light much more valuable for therapeutic benefits.
Monochromatic non-coherent light, such as light from
LED's can be useful for superficial tissues such as
wounds. In comparative studies, however, lasers have
shown to be more effective than monochromatic
non-coherent light sources. Non-coherent light will
not be as effective in deeper areas.
Laser light has unique physical properties, which no
ordinary light has. This is the key to why laser
light is so effective compared to other kinds of
light in healing.
LED based systems have gradually improved during the
years and are now better documented. Because of lack
of scientific support in the past, some
manufacturers have quoted laser research as proof of
the effectiveness of LED therapy, meaning that they
are one and the same. Such argumentation should be a
“warning lamp” to the customer.
LED’s can easily be arranged in “clusters” to cover
large areas, while this is quite possible but less
common with lasers. Combining LED’s and lasers in
the same cluster is sometimes found, but the
usefulness has not been documented.
Does the coherence of
the laser light disappear when entering the tissue?
No. The length of coherence, though,
is shortened. Through interference between laser
rays in the tissue, very small "islands" of more
intense light, called speckles occur. These speckles
will be created as deep as the light reaches in the
tissue and within a speckle volume, the light is
partially polarized. It is easy to show that
speckles are formed rather deep down in tissue and
the existence of real speckles proves that the light
What are the major
differences between laser light and conventional
Laser light is monochromatic (narrow
spectrum, specific wavelength) and coherent
What does radiation
mean when you are speaking of Lasers?
"Radiation" is often misinterpreted
since it is also used to describe radioactive
materials and ionized radiation. The use of the word
"radiation" in terms of laser light is merely an
expression of energy transmission.
What is a joule?
A joule is a measure
of energy generated by laser.
What are the
biological effects of laser light emitted from LLLT
• Increased cell metabolism
• Simulated cell growth
• Cell regeneration
• Increased tissue activity
• Edema reduction
• Reduced fibrous tissue formation
• Stimulated nerve function
• Collagen deposition
lasers damage the eye?
Yes and no! Read the following:
The following factors are of importance regarding
the eye risk of different lasers:
The divergence of the light beam. A parallel light
beam with a small diameter is by far the most
dangerous type of beam. It can enter the pupil, in
its entirety, and be focused by the eye's lens to a
spot with a diameter of hundredths of a millimeter.
The entire light output is concentrated on this
small area. With a 10 mW beam, the power density can
be up to 12,000 W/cm2 the output power (strength) of
the laser. It is fairly obvious that a powerful
laser (many watts) is more hazardous to stare into
than a weak laser.
The wavelength of the light within the visible
wavelength range, we respond to strong light with a
quick blinking reflex. This reduces the exposure
time and thereby the light energy which enters the
eye. Light sources which emit invisible radiation,
whether an infrared laser or an infrared diode,
always entail a higher risk than the equivalent
source of visible light. Radiation at wavelengths
over 1400 nm is absorbed by the eye's lens and is
thus rendered safe, provided the power of the beam
is not too high. Radiation at wavelengths over 3,000
nm is absorbed by the cornea and is less dangerous.
The distribution of the light source
the light source is concentrated, which is often the
case in the context of lasers, an image of the
source is projected on the retina as a point,
provided it lies within our accommodation range,
i.e. the area in which we can see clearly. A widely
spread light source is projected onto the retina in
a correspondingly wide image, in which the light is
spread over a larger area, i.e. with a lower power
density as a consequence. For example: a clear light
bulb (which is apprehended as a more concentrated
light source) penetrates the eye more than a
so-called "pearl" light bulb. A laser system with
several light sources placed separately, such as a
multi-probe (the probe is the part of the laser you
hold and apply to the area to be treated; a single
probe means there is only one laser diode in the
probe, as opposed to a multi- probe, which has
several laser diodes) with several laser diodes,
can, seen as a whole, be very powerful but at the
same time constitute a smaller hazard to the eye
than if the entire power output was from one laser
diode, because the diodes' separate placement means
that they are reproduced in different places on the
We have often heard this kind of remark: "If it's a
class 3B laser then it's fine, otherwise it has no
effect. This is of course entirely incorrect and has
lead to a situation where manufacturers have
produced lasers to meet the 3B classification, so
that they will sell in greater volumes. Let us look
at a couple of examples:
A GaAlAs laser with a wavelength of 830 nm, an
output of 1 mW and a well collimated beam (1 mrad
divergence) is classified as laser class 3B as it is
judged to be hazardous to the eyes. The reason for
this is partly the collimated beam, and partly the
wavelength, which is just outside the visible range
and hence provokes no blink reflex in strong light.
A HeNe laser with a wavelength of 633 nm, an output
of 10 mW and divergent beams (1 rad divergence,
which corresponds to a cone of light with a top
angle of about 57°) is classified as laser class 3A
because, owing to its divergence, it cannot damage
With the recent advent of "high power low power
lasers", i.e. GaAlAs lasers in the range 100-500 mW
there is another story. These lasers are indeed
dangerous for the eyes and should only be used by
qualified persons and with proper protective
(pulsing) should be used for the various therapies?
First we must differentiate between
“chopping” and “super pulsing”. Some lasers, like
the GaAs laser, are always pulsed. The pulses are
very short but the peak power in the pulse is very
high, several watts, but the pulse duration is
typically only 200 nanoseconds. Other lasers like
the HeNe and the GaAlAs are always continuous, but
can be “pulsed” by mechanical or electrical devices.
This means that the beam is turned off and on but
the output of each pulse is still the same.
When pulsing one generally loses power. With most
GaAs lasers the power decreases with lowered
frequencies (unless there is a pulse train
arrangement) and with “chopped” lasers, we typically
loose 50% (50% duty cycle). The output is of course
the same in the pulses but since it is turned off
50% of the time, treatment time must be extended.
There is sound evidence from cell studies that the
pulsing makes a difference. But the evidence from
clinical studies is almost absent. Since GaAs is
always pulsed, we have to choose a frequency and
then to use the anecdotal evidence there is. But the
loss of power on lowered frequencies must be
observed! For other lasers the choice of frequency
is pure guesswork.
How many treatments
will I need, and how often will I need to get the
In order to heal the tissues quickly
and to maintain the cells in biostimulation, a
patient comes in for a treatment several times a
week for a half hour each time. The average number
of treatments can range anywhere from 15-25,
depending on the severity of the condition. The less
severe or acute the condition, the fewer number of
treatments required. The more severe or more chronic
the condition, the greater the number of treatments