Laser & Light Therapy

What is Laser Therapy?

• Light Amplification by the Stimulated Emission of Radiation

• Compressed light of a wavelength from the cold, red part of the spectrum of electromagnetic radiation

• Monochromatic - single wavelength, single color• Coherent - travels in straight line• Polarized - concentrates its beam in a defined

location/spot

History• Albert Einstein – 1st described this theory that was transformed in

to laser therapy

• By the end of the 60’s, Endre Mester (Hungary) -– was reporting on wound healing through laser therapy

• In early 1960’s, the 1st low level laser was developed.

• In Feb. 2002, the MicroLight 830 (ML830) received FDA approval for Carpal Tunnel Syndrome Treatment (research treatment)

• Laser therapy – has been studied in Europe for past 25-30 years; US 15-20 years

What’s in a Name?• Therapeutic Laser• Low Level Laser

Therapy• Low Power Laser

Therapy• Low Level Laser• Low Power Laser• Low-energy Laser• Soft Laser• Low-reactive-level

Laser

• Low-intensity-level Laser

• Photobiostimulation Laser

• Photobiomodulation Laser

• Mid-Laser• Medical Laser• Biostimulating

Laser• Bioregulating Laser

What Does It Do?

• Laser light waves penetrate the skin with no heating effect, no damage to skin & no side effects.

• **Laser light directs biostimulative light energy to the body’s cells which convert into chemical energy to promote natural healing & pain relief.

• Optimizes the immune responses of blood & has anti-inflammatory & immunosuppressive effects.

Physiological Effects• Biostimulation – improved metabolism, increase

of cell metabolism– Increases speed, quality & tensile strength of tissue

repair• Improved blood circulation & vasodilation

– Increases blood supply• Increases ATP production• Analgesic effect

– Relieves acute/chronic pain• Anti-inflammatory & anti-edematous effects

– Reduces inflammation

Physiological Effects• Stimulation of wound healing

– Promotes faster wound healing/clot formation– Helps generate new & healthy cells & tissue

• Increase collagen production– Develops collagen & muscle tissue

• Increase macrophage activity– Stimulates immune system

• Alter nerve conduction velocity– Stimulates nerve function

Tissue & Cellular Response• Red light affects all cell types

– Absorbed by the mitochondrial present in all cells– Cytochromes (respiratory chain enzymes) within the

mitochondria have been identified as the primary biostimulation chromophores (primary light-absorbing molecules).

– Since enzymes are catalysts with the capability of processing thousands of substrate molecules, they provide amplification of initiation of a biological response with light.

• Infrared light is more selective absorbed by specific proteins in the cell membrane & affects permeability directly

Tissue & Cellular Response• Cytochromes function to couple the release of

energy from cellular metabolites to the formation of high energy phosphate bonds in adenosine triphosphate (ATP) – ATP is used to drive cell metabolism (maintain

membrane potentials, synthesize proteins & power cell motility & replication).

• Assuming cytochromes also can absorb energy directly from illumination, it is possible that during LLLT light energy can be transferred to cell metabolism via the synthesis of ATP.

Mitochondria

Tissue & Cellular Response• Magnitude of tissue’s reaction are based on physical

characteristics of:– Output wavelength/frequency– Density of power– Duration of treatment– Vascularity of target tissues

• Direct effect - occurs from absorption of photons • Indirect effect – produced by chemical events caused

by interaction of photons emitted from laser & the tissues

• LASERs - classified by the FDA’s Center for Devices & Radiological Health based on the Accessible Emission Limit (AEL).

• Class Levels 1-4 • 1 = incapable of producing damaging radiation levels (laser printers

& CD players)• 2 = low-power visible lasers (400-700 nm wavelength, 1 mW)• 3 = medium-power lasers - needs eye protection

• 3a – up to 5 mW• 3b** – 5 mw-500 mW

• 4 = high-power lasers– presents fire hazard (exceeds 500 mW)

LASER Regulation

Laser Generators• Components of a generator:

• Power supply – electrical power supply that can deliver up to 10,000 volts & 100’s amps

• Lasing medium – gas, solid, liquid• Pumping device –

– high voltage, photoflash lamps, radio-frequency oscillators or other lasers (pumping is used to describe the process of elevating an orbiting electron to a higher, excited energy level)

• Optical resonant cavity – contains lasing medium

Types of Lasers• 4 categories of lasers

– Crystal & Glass (solid - rod)• Synthetic ruby & others (synthetic ensures purity)

– Gas (chamber) – 1961• HeNe, argon, CO2, & others (HeNe under investigation)

– Semiconductor (diode - channel) - 1962• Gallium Arsenide (GaAs under investigation)

– Liquid (Dye) - Organic dyes as lasing medium

– Chemical – extremely high powered, frequently used for military purposes

High vs. Low Level Lasers

• High – Surgical Lasers– Hard Lasers– Thermal– Energy – 3000-10000

mW

• Low– Medical Lasers– Soft Lasers– Subthermal– Energy – 1-500 mW– Therapeutic (Cold)

lasers produce maximum output of 90 mW or less

– 600-1000 nm light

Infrared Light Therapy

• SLD – Super Luminous Diode– Brighter

• LED – Light Emitting Diode

Laser Light Properties• Monochromaticity

• 1 color – 1 wavelength• <400 nm • Ultraviolet spectrum

• Coherence• Waves same length & traveling in same phase relationship• 400-700 nm• Visible

• Collimation• Degree to which beam remains parallel with distance• 700-10,000 nm• Infrared

Parameters

• Patient– Need medical

history & proper diagnosis• Diabetes – may

alter clinical efficacy

– Medications • Photosensitivity

(antibiotics)– Pigmentation

• Dark skin absorbs light energy better

• Laser – Wavelength– Output power– Average power – Intensity– Dosage

Parameters - Wavelength

• Nanometers (nm)• Longer wavelength (lower frequency) =

greater penetration• Not fully determined• Wavelength is affected by power

Parameters – Power• Output Power

– Watts or milliwatts (W or mW)– Important in categorizing laser

for safety– Not adjustable

• Power Density (intensity)– W or mW/cm2

– Takes into consideration – actual beam diameter If light spread over lager area – lower power density

– Beam diameter determines power density

• Average Power– Continuous or pulse-train

(burst) frequency mode– Knowing average power is

important in determining dosage with pulsed laser

– If laser is continuous – avg. power = peak output power

– If laser is pulsed (burst) then avg. power is = to peak output power X duty cycle

Parameters – Energy Density

• Dosage (D)• Amount of energy applied per unit area• Measured in Joules/square cm (J/cm2)

– Joule – unit of energy– 1 Joule = 1 W/sec

• Dosage is dependent on:– Output of laser in mW– Time of exposure in seconds– Beam surface area of laser in cm2

• Various dosage ranges per site (1-9 J/cm2)

Parameters – Energy Density

• Recommended Dosage Range– Therapeutic response = 0.001-10 J/cm2

– Minimal window threshold to elicit response– Too much – suppressive effect– Open wounds – 0.5-1.0 J/cm2

– Intact skin – 2.0-4.0 J/cm2 – Average treatment – 6 /cm2

Helium Neon Lasers• Uses a gas mixture in a pressurized tube

• Now available in semiconductor laser• Emits red light• Wavelength: 632.8 nm• Power output: 1.0-25.0 mW • Energy depth: 6-10 mm

• The higher the output lasers (even though they are still low power) allow reduced delivery time

Indium-Gallium-Aluminum-Phosphide

• InGaAip• Replacing HeNe lasers• Semiconductor • Wavelength: 630-700 nm• Power output: same as HeNe• Energy depth: superficial wound care

Gallium Arsenide

• Semiconductor - produces an infrared (invisible) laser

• Wavelength: 904–910 nm • Power output: may produce up to 100 mW• Energy depth: 30-50 mm• Short pulse-train (burst) duration (100-200 ns)

Gallium Aluminum Arsenide

• GaAIAs• Semiconductor• Wavelength: 780-890 nm• Power Output: 30-100 mW (up to 1000 mW)

• Energy Depth:

What Does it Look Like?

• http://www.laserhealthsystems.com/omegaofferings.htm

• http://www.thorlaser.com/products/

Indications

• Indications– Soft tissue injuries– Fractures– Osteoarthritis, Rheumatoid Arthritis– Pain– Wounds & Ulcers– Acupuncture

Contraindications• Contraindications

– Application over eyes– Possibly can damage cellular structure or DNA– Cancerous growths– Pregnancy – over & around uterus– Over cardiac region & Vagus nerve– Growth plates in children– Over & around thyroid gland & endocrine glands– Patients who have been pre-treated with one or more

photosensitizers

Treatment Precautions• Better to underexpose than to overexpose• Avoid direct exposure into eyes (If lasing for extended

periods of time, safety glasses are recommended)

• May experience a syncope episode during treatment during chronic pain, but very rare

• If icing – use BEFORE phototherapy– Enhances light penetration

• If using heat therapy – use AFTER phototherapy – Decreases light penetration

Treatment Techniques• Gridding Technique

• Divide treatment areas into grids of square centimeters

• Scanning Technique• No contact between laser tip in skin; tip is held 5-10

mm from wound• Wanding Technique

• A grid area is bathed with the laser in an oscillating fashion; distance should be no farther than 1 cm from skin

• Point Application (Acupuncture point)

Treatment Techniques

• Simple• For general application, only treatment time & pulse rate vary• Dosage

• Most important variable in laser therapy & may be difficult to determine because of the above conditions

• Handheld applicator• Tip should be in light contact with skin while laser is engaged for

calculated time

• Maintain laser perpendicular to treatment surface• Firm contact unless open wound• Clean area prior to treatment• Begin with minimal treatment and gradually increase• Check for pre/post-treatment changes• Ask the patient how they are doing prior to next treatment

– May have to adjust dosage

• Dynatron’s Solaris D880 Infrared Therapy– 880 nm wavelength – SLD (32 ) (deep)– 660 nm – LED (4) (superficial)– 10 minute max. treatment or 60 Joules– Place probe on treatment area. Maintain constant

contact with the skin.• Do not bathe the area with the probe.

– FDA cleared to “provide topical heating for temporary increase in blood circulation, temporary relief of minor muscle & joint aches, pain & stiffness & relaxation of muscles; for muscle spasms & minor pain & stiffness associated with arthritis.”• Dynatron Solaris 709

MedX Laser & Light Therapy

• Laser probe• SLD (2)

Miscellaneous

• www.geocities.com/altmedd/laser.htm

• http://laserhealing.net/lowlevel.html

• Journal of Laser Therapy– www.walt.nu/journal.htm