Therapeutic LASER

Therapeutic LASER

1. Therapeutic LASER Sohel Ahmed MPT (Sports)

2. Overview Laser is an Acronym for the L ight A mplification by the S timulated E mission of R adiation 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

6. 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

7. Laser Generators

8. 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 .

9. Classification of laser According to nature of the material placed between two reflecting surfaces . According to intensity According to hazards

10. 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 )

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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

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

19. 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.

20. 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.

21. 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.

22. 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)).

23. 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).

24. 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

25. Physiological effects Increase bone and cartilage formation: b y stimulation of bone morphogenetic proteins that stimulate bone cell differentiation)

26. 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

27. 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

28. 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

29. 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.

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

31. 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

32. Depth of Penetration 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. 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.

33. 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

34. Treatment Techniques Gridding Technique Scanning Technique Wanding Technique

35. 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.

36. 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.

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

38. Thank you