Therapeutic LASER

1. Therapeutic LASER
Sohel Ahmed
MPT (Sports)

2. Overview
• Laser is an Acronym for the Light Amplification by the Stimulated
Emission of Radiation
• Compressed light of a wavelength from the cold, red part of the
spectrum of electromagnetic radiation
• Therapeutic laser is also known as Soft laser, Cold laser, Low intensity
laser, class III A &B and class iv laser
• Laser is a beam of light which is used for various purposes

3. History
• Albert Einstein 1916 – 1st described this theory that was transformed in to laser
therapy
• In 1955, Townes showed it was possible to produce stimulated emission of
microwaves beyond the optical region of the electromagnetic spectrum
• By the end of the 60’s, Endre -was reporting on wound healing through laser
therapy
• In early 1960’s, the 1st low level laser was developed
• Laser therapy – has been studied in Europe for past 25-30 years; US 15-20 years

4. Physics
• Photon: The basic unit of light; a packet or quanta of light energy
• Gain medium: A material (gas, liquid, solid) with specific optical
properties contained inside an optical chamber
• Stimulated emission: This occurs when photons are ejected through
the semitransparent mirror appearing as a beam of light

5. Physics
• Coherence: Property of identical phase and time relationship. All
photons of laser light are the same wavelength
• Monochromaticity: The condition that occurs when a light source
produces a single color or wavelength
• Collimation: To make parallel

7. 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

8. Laser Generators

10. Low level laser therapy
• Low-level laser therapy (LLLT) is a pain-free, non-invasive, affordable
tool used by physical therapists throughout the healing process that is
becoming more prevalent in PT practices nationwide .

11. Classification of laser
1. According to nature of the material placed between two reflecting
surfaces.
2. According to intensity
3. According to hazards

12. 1. According to nature of the material placed
between two reflecting surfaces
a) Crystal lasers (solid state lasers) include
- Ruby crystal (aluminum oxide and chromium)
b) Gas lasers include
- Helium neon (HeNe)
- Argon
- Carbon dioxide (CO2)

13. 1. According to nature of the material placed
between two reflecting surfaces
c) Semiconductor or diode laser
- Gallium arsenide (GaAs)
d) Liquid laser
- Polyphenyle - Oxazine
e) Chemical laser
- Laser with high intensity not used therapeutically but used in
industrial production

14. 2. According to intensity
High power: known as "hot" lasers because of the thermal responses
they generate. These are used in the medical realms in numerous
areas, including surgical cutting and coagulation, ophthalmologic,
dermatologic, oncologic, and vascular specialties

15. 2. According to intensity
Low power: known as "low power laser therapy" or "low level laser
therapy". It used for wound healing and pain management. These
lasers produce a maximal output of less than 1 milliwatt causing
photochemical, rather than thermal effects. No tissue warming occurs

16. 3. According to hazards
Class 1 (less than 0.5 mW)
• Visible and non-visible
• No eye or skin danger
• Laser printers, car entry, CD players
• No heating/no healing
• Safe in all uses unless focused through magnifier

17. 3. According to hazards
Class 2 (less than 1 mW)
• Visible
• Safe for short periods on eyes and extended on skin
• Safe because blink reflex limits retina exposure
• No healing/no heating

18. 3. According to hazards
Class 3 (1mW to 500 mW)
• Visible and invisible.
• Helium neon (HeNe)
• Galium Arsenide (GaAs)—infrared
• Protective eye ware if direct viewing of beam

19. 3. According to hazards
Class 4 (more than 500 mW)
• Increases tissue temperature--can burn
• Dehydrates tissue
• Coagulates protein
• Thermolysis
• CO2, Argon
• Eye danger can result from indirect or reflected beam

20. Most Commonly Used Lasers
• Helium neon (HeNe)
• Gallium arsenide (GaAs)

21. Helium neon (HeNe)
• The HeNe gas laser uses a gas mixture of primarily helium with neon in a
pressurized tube.
• This creates a laser in the red portion of the electromagnetic spectrum with a
wavelength of 632.8 nm. The power output of the HeNe can vary, but typically
runs from 1.0 to 10.0 mW, depending on the gas density used.

22. Gallium arsenide (GaAs)
• The GaAs lasers utilize a diode to produce an infrared (invisible) laser at a
wavelength of 904 nm. Diode lasers are composed of semiconductor
silicone materials that are precisely cut and layered. An electrical source is
applied to each side, and lasing action is produced at the junction of the
two materials. The cleaved surfaces function as partially reflecting surfaces
that will ultimately produce coherent light.
• The 904-nm laser is delivered in a pulsed mode because of the heat
produced at the junction of the diode chips.

24. Physiological effects
Reducing Pain
There is an increase in serotonin (5-HT) levels (inhibit pain transmission to brain and from
nociceptors).
There are also increases in Beta Endorphins, which decrease pain sensation.
Decrease bradykinins (is an inflammatory mediator. It is a peptide that causes blood vessels to
dilate which can be prevalent in injured tissue, induce pain sensation by stimulating nociceptive
afferents
Increase release of Acetylcholine: Acetylcholine helps normalize nerve signal transmission in the
autonomic and somatic pathways.

25. Physiological effects
Reducing Inflammation
• Enhancement of ATP by stimulation of mitochondria.
• Stabilization of the Cellular Membrane.
• Acceleration of Leukocytic Activity
• Increased Angiogenesis (is the physiological process through which new
blood vessels form by vascular endothelial cells in proliferation (growth of
new tissue)).

26. Physiological effects
Promoting Tissue Healing
a. Increased macrophage activity.
b. Increased fibroblast proliferation.
c. Keratinocyte proliferation. (Keratinocyte: the outermost layer of the skin. The primary
function of keratinocytes is the formation of a barrier against environmental damage by
pathogenic bacteria, fungi, parasites, and viruses, heat, UV radiation)
c. Growth factors increase (Growth factors: act on stimulating cellular growth, proliferation and
healing. Examples are fibroblast growth factors and vascular endothelial growth factors
stimulate blood vessel differentiation (angiogenesis).

27. Physiological effects
Recovery from nerve injury
• Accelerate nerve regeneration ( by stimulation of Nerve growth
factor)
• Increase frequency of action potential
• Increase rate of nerve conduction

28. Physiological effects
Increase bone and cartilage formation: by stimulation of bone
morphogenetic proteins that stimulate bone cell differentiation)

29. Indications of laser therapy
1. Dermatological disorders
• Wounds
• Ulcers
2. Pain and inflammation in orthopedic and sport cases
• Ankle sprain
• Chronic Low back pain
• Tennis Elbow
• Plantar fasciitis
• Frozen shoulder
• OA
3. Neurogenic pain
• Trigeminal neuralgia

30. Dangers and contraindications
• Effects on eyes: Risk of eye damage if the beam is applied directly into the eye.
So, to avoid the exposure of eye with a beam of laser, protective goggles should
be worn by the patient as well as by the physiotherapist
• Effects on cancerous growth: Laser acts as a photobiostimulatory agent, its
exposure to cancerous tissue can lead to acceleration of its growth and
metastasis
• Effects on pregnant uterus: Laser should not be applied directly over the
pregnant uterus as it may cause abnormal growth

31. Dangers and contraindications
• Effects on infected tissues: When treated in contact with the infected tissue, the
laser head needs to be cleaned or sterilized. It should be used preferably in
conjunction with ultraviolet therapy for the treatment of infected wounds
• Hemorrhagic areas: Laser can cause vasodilatation and hence, care should be
taken while exposing any hemorrhagic area
• Cardiac conditions: Patients of certain cardiac conditions are avoided the
exposure of laser therapy around the cardiac region

32. Precautions
• LLLT should not be applied within 6 months of radiation therapy.
• Because of unknown effects, lasers should not be applied over unfused epiphyseal
plates, or be administered to small children.
• The patient may experience dizziness during the treatment. If this occurs, discontinue
the treatment. If the episode recurs, laser therapy should not be applied to the patient.
• Caution should be used with patients who are taking medications that increase
sensitivity to light including certain antihistamines, oral contraceptives, NSAIDs,
tetracyclines, and antidepressants.
• Some tattoo inks may increase the absorption of laser energy.

33. Clinical application of laser
1. Calculation of laser dose
2. Penetration of laser
3. Techniques of laser

34. Calculation of laser dose
Calculation of laser dose dependent on:
• The output power of the laser in mw
• The time of exposure in seconds
• The beam surface area of the laser in cm2 (area of irradiation)
T A = (E/P av ) × A
T A = treatment time for a given area
E = mJ of energy per cm 2
P av = Average laser power in mW
A = beam area in cm 2
For example: To deliver 1 J/cm 2 with a 0.4 mW average-power GaAs laser with a 0.07 cm 2 beam area:
T A = (1 J/cm 2 /0.0004 W) × 0.07 cm 2
= 175 sec or 2:55 min

36. Depth of Penetration
a) HeNe laser energy Absorbed rapidly in the
superficial structures, especially within the first 2-5
mm of soft tissue. The response that occurs from
absorption is termed the "direct effect." HeNe laser
has an indirect effect on tissues up to 8-10 mm.
b) The GaAs, which has a longer wavelength, is directly
absorbed in tissues at depths of 1-2 cm and has an
indirect effect up to 5 cm.

37. Laser treatment techniques
There are two main techniques
1. Contact technique: GaAs only for trigger points or around wound.
2. Non-contact technique: for HeNe and GaAs for superficial wounds or
stimulation of wound bed

38. Treatment Techniques
• Gridding Technique
• Scanning Technique
• Wanding Technique

39. Gridding Technique
An imaginary grid should be drawn over the
area to be treated and each square
centimeter of the injured area should be
lasered for the specified time. The laser
should be in light contact with the skin.

40. Scanning Technique
When skin contact cannot be maintained,
the application should be held in the center
of the square centimeter grid at a distance
of less than1 cm and should be at an angle
of 30° to the surface being treated.

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

42. Thank you