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Light Therapy

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  • 1. Light Therapy With adaptations from Therapeutic Modalities: Art & Science , Knight & Draper (2008) for KIN 195
  • 2. Light Therapy
    • Also called phototherapy
    • Application of light from a variety of devices for a variety of therapeutic purposes
    • Devices include
      • Lasers
      • Light-emitting diodes (LEDs)
      • Super-luminous diodes (SLDs)
      • Fluorescent lamps
      • Infrared lamps
      • Ultraviolet lamps
      • Diachronic lamps
  • 3. Confusion: Many Names
    • Terms and acronyms used to describe light therapy
      • Phototherapy
      • Cold laser
      • Soft laser
      • Low-energy laser
      • Low level-laser therapy (LLLT),
      • Low-energy laser therapy (LELT)
      • Low-intensity laser activated biostimulation (LILAB)
      • Low-power laser irradiation (LPLI)
      • Low-power laser therapy (LPLT)
      • Low-intensity laser (LIL)
      • Monochromic infrared energy
  • 4.
    • Began with lasers in 1970s
      • Acronym for light amplification by stimulated emission of radiation
      • Transforms electromagnetic energy
        • (in or near the range of visible light) into
        • Extremely intense, small, nearly nondivergent beam
        • Monochromatic radiation
        • All waves in phase
    Light Therapy: History
  • 5. Lasers and LEDs/SLDs
    • LED
      • Special type of semiconductor diode that emits visible light when electric current passes through it
    • SLD
      • A brighter LED
    • Both lasers and LED/SLDs deliver light of specific wavelength
      • But light is generated differently
      • Some characteristics different
    • No consensus about relative merits of these two technologies
      • So difficult to discuss their therapeutic value
      • Major problem is with terminology.
  • 6. LEDs and SLDs (cont.)
    • However, light is monochromatic and not coherent
      • More scattered than laser
      • Less will strike target
      • Less energy imparted to target
  • 7. Laser Light vs. Normal Light
    • Very different
    • Laser light Normal light
      • Monophasic Multiphasic
      • Monochromatic Multichromatic
      • Coherent Incoherent
      • Nondivergent Divergent
      • (directional)
    • That is . . .
  • 8. Laser Light vs. Normal Light (cont.)
    • An LED emits light with waves of the same frequency (monochromatic) but out of phase (incoherent)
  • 9. Laser Light vs. Normal Light (cont.)
    • A laser emits light with waves of the same frequency (monochromatic) and in phase (coherent).
  • 10. Laser Light Terminology
    • Light
      • Electromagnetic radiation that produces a visual sensation
    • Amplify
      • Increase in size, volume, or significance
    • Stimulate
      • To excite or invigorate
      • To encourage or provoke something to grow, develop, or become more active
  • 11. Laser Light Terminology (cont.)
    • Emission
      • A flowing forth, such as the release of electrons from parent atoms
    • Radiation
      • Energy transmitted as rays, waves, or particles
  • 12. Laser Light Terminology (cont.)
    • Nondivergent
      • Incapable of separating or widening
      • Contrast the light from a laser pointer (nondivergent) with that coming from a flashlight (divergent).
  • 13. Laser Devices
    • Many, each with a specific frequency, amplification, and beam focus
    • Not interchangeable
      • Can’t treat wounds with TV tuner
  • 14. Laser Energy Production
    • External energy is applied to medium.
  • 15. Laser Energy Production (cont.)
    • Causes spontaneous release of photons, some of which (P6) reflect back and forth between the two mirrors
  • 16. Laser Energy Production (cont.)
    • Leads to intense photon resonance, part of which is released as laser light through the half-slivered mirror.
  • 17. Laser Classification
    • Classified by lasing medium and safety
      • Often referred to by color
        • Imprecise
          • For example, UV includes waves of 150–380 nm
          • But response to 150 nm waves different from that to 380 nm waves
      • Avoid this practice.
  • 18.
    • Gas
      • Helium and helium neon (HeNe) most common
    • Diode or semiconductor
      • Either small and low powered or large and high powered
      • Low power
        • Laser pointers, laser printers, and compact disc players
        • 780 nm aluminum gallium arsenide (AlGaAs) laser diode used in CD players is most common type of laser
      • Large industrial diode lasers can generate great amounts of heat
        • Used for cutting and welding
    Laser Classification by Medium
  • 19.
    • Dye
      • Uses large-molecule organic dyes in a liquid solution
      • Can be tuned to produce broad range of wavelengths
    • Solid state
      • Uses various minerals
      • Examples
        • Ruby, neodymium:yttrium-aluminum-garnet (YAG) lasers
    Laser Classification by Medium (cont.)
  • 20. Laser Classification by Medium (cont.)
    • Type Medium Wavelength (nm) Safety
      • Gas HeNe 633 I–IV
      • Gas CO2 10,600 IIIb–IV
      • Gas Argon 488–514 IV
      • Diode* AlGaAs 600–1000 IIIb
      • Dye Tunable dye 577 IV
      • Solid state Ruby 694 IV
      • Solid state HdYag 1060 IV
      • Excimer Dimer 351 IV
    * Semiconductor.
  • 21. Laser Classification by Safety (cont.)
    • Power
    • Class (mW) Visible Safety Concerns
    • I <0.5 Either* None
    • II <1 Visible Safe for momentary viewing;
    • IIIa <5 Either Photochemical effect
    • IIIb <500 Either Photobiomodulation, no photothermal effect,
    • no harm to skin or clothing, potential damage to eye
    • IV >500 Either Photothermal effect,
    • harmful to skin, eyes, and
    • clothing, use with extreme caution
    * Either , both visible and nonvisible.
  • 22. Tissue Penetration of Various Wavelengths
      • Wavelength (nm) Color Range Penetration (mm)
    • 150–380 UV <0.1
    • 390–470 Violet to deep blue ~0.3
    • 475–545 Blue to green ~0.3–0.5
    • 545–600 Yellow to orange ~0.5–1.0
    • 600–650 Red ~1.0–2.0
    • 650–1,000 Deep red to IR 2 0–3.0
    • 1,000–1,350 Near to mid-IR 3 0–5.0
    • 1,350–12,000 IR <0.1
  • 23. Johnson D. Defining “The Specs” of Phototherapy Devices. NATA News ; 2007. 10:16-18.
  • 24.
    • When absorbed, specific wavelengths of laser light cause specific physiological responses.
    • Therapeutic value of responses debated.
      • Industry continues to grow
    • Now using nonlaser devices
      • LEDs, SLDs, polarized polychromic light
      • Deliver light of specific wavelength to body
    Laser Theory
  • 25. Photobiomodulation
    • Act of modifying biological processes with light
      • Stimulate or inhibit molecules or structures
      • Modify healing and pain
  • 26. Photobiomodulation (cont.)
      • Following occur in tissue cultures (not confirmed by clinical trials)
        • Photobiomodulation of cellular events
        • Stimulated/optimized tissue repair
        • Pain relief
  • 27. UV Radiation
    • A portion of electromagnetic spectrum that produces chemical reactions in microorganisms, epidermis, and dermis
    • Effects are superficial and mainly chemical
    • Used therapeutically to destroy superficial infectious organisms and other microorganisms
    • Easy to misuse
  • 28. UV Radiation (cont.)
    • Incorrect application may cause dermatitis
      • Local ulceration
      • Impetigo
      • Folliculitis
      • Herpes simplex
    • Overexposure can lead to
      • Increased sensitivity to ordinary sunlight
      • Cancer
    • Generally used by dermatologists
    • Rarely by athletic trainers or physical therapists
  • 29. Proposed mechanism of light therapy (Enwemeka & P ö ntinen, 2005)
  • 30. Light therapy research findings
    • Robert A. de Bie , Henrica C. W. de Vet, Ton F. Lenssen, Frans A. J. M. van den Wildenberg, Gauke Kootstra and Paul G. Knipschild. Low-level laser therapy in ankle sprains: A randomized clinical trial. Archives of Physical Medicine and Rehabilitation (1998) 79: 1415-1420.
    • Conclusions: Neither high- nor low-dose laser therapy is effective in the treatment of lateral ankle sprains. accepted 28 April 1998. 
  • 31. Light therapy research findings, cont.
    • Arne Nyholm Gam, Hanne Thorsen and Frank Lønnberg. The effect of low-level laser therapy on musculoskeletal pain: A meta-analysis. Pain (1993) 52: 63-66.
    • We conclude that Low Level Laser Therapy has no effect on pain in musculoskeletal syndromes.
  • 32. Jeffrey R. Basford, Gerard A. Malanga, David A. Krause, and William S. Harmsen. A randomized controlled evaluation of low-intensity laser therapy: Plantar fasciitis. Archives of Physical Medicine and Rehabilitation; (1998) 79: 249-254.
    • Subjects: Thirty-two otherwise healthy individuals with plantar fasciitis of more than 1 month's duration.
    • Intervention: Dummy or active irradiation with a 30mW .83μm GaAlAs continuous-wave infrared (IR) diode laser three times a week for 4 weeks.
    • Measurements: Morning pain, pain with toe walking, tenderness to palpation, …
    • Results: No significant differences were found between the groups in any of the outcome measures either during treatment or at the 1-month follow-up. Treatment, however, was well tolerated and side effects were minimal.
    • Conclusions: Low-intensity IR laser therapy appears safe but, at least within the parameters of this study, is not beneficial in the treatment of plantar fasciitis.
  • 33. T Karu. Primary and secondary mechanisms of action of visible to near-IR radiation on cells. Journal of Photochemistry and Photobiology B: Biology ,  (March 1999) Volume 49, Issue 1, Pages 1-17.
  • 34. JR. Basford, CG. Sheffield, KR. Cieslak Laser therapy: A randomized, controlled trial of the effects of low intensity Nd:YAG laser irradiation on lateral epicondylitis. Archives of Physical Medicine and Rehabilitation (November 2000) Volume 81, Issue 11, Pages 1504-1510.
    • Treatment with low intensity 1.06-μm laser irradiation within the parameters of this study was a safe but ineffective treatment of lateral epicondylitis.
    • All underwent irradiation for 60 seconds at 7 points along the symptomatic forearm 3 times weekly for 4 weeks by a masked therapist. The sole difference between the groups was that the probe of a 1.06-μm continuous wave laser emitted 204mW/cm2 (12.24J/cm2) for the treated subjects and was inactive for the control subjects. Subjects were assessed at the beginning, midpoint (session 6), and end (session 12) of treatment, as well as at follow-up 28 to 35 days after their last treatment.
  • 35. JR. Basford, CG. Sheffield, WS. Harmsen. Laser therapy: A randomized, controlled trial of the effects of low-intensity Nd:YAG laser irradiation on musculoskeletal back pain. Archives of Physical Medicine and Rehabilitation (June 1999): Volume 80, Issue 6, Pages 647-652.
    • Treatment with low-intensity 1.06μm laser irradiation produced a moderate reduction in pain and improvement in function in patients with musculoskeletal low back pain. Benefits, however, were limited and decreased with time. Further research is warranted.
    • All underwent irradiation for 90 seconds at eight symmetric points along the lumbosacral spine three times a week for 4 weeks by a masked therapist. The sole difference between the groups was that the probes of a 1.06μm neodymium: yttrium-aluminum-garnet laser emitted 542mW/cm2 for the treated subjects and were inactive for the control subjects
  • 36. MA. Naeser, KK. Hahn, BE. Lieberman, KF. Branco. Carpal tunnel syndrome pain treated with low-level laser and microamperes transcutaneous electric nerve stimulation: A controlled study. Archives of Physical Medicine and Rehabilitation (July 2002): Volume 83, Issue 7, Pages 978-988.
    • Significant decreases in McGill Pain Questionnaire score, median nerve sensory latency, and Phalen and Tinel signs after the real treatment series but not after the sham treatment series.
    • Patients could perform their previous work (computer typist, handyman) and were stable for 1 to 3 years.
  • 37. E Haker, T Lundeberg. Is low-energy laser treatment effective in lateral epiconylagia? Journal of Pain and Symptom Management (May 1991);Volume 6, Issue 4,  Pages 241-246 .
    • Forty-nine patients were consecutively assigned at random to two groups, laser or placebo. The Mid 1500 Irradia laser was used with the following parameters: wavelength 904 nm; average power output 12 mW; peak value 8.3 W; frequency 70 Hz (pulse train 8000 Hz). The laser (Ga-As) was locally applied to 6 sites on and around the epicondyle. Each point was treated for 30 sec, resulting in a dose of 0.36 J/point and an area of treatment of 0.2 mm2. Patients were treated 2–3 times weekly, for a total of 10 treatments. Follow-ups were done after three and 12 mo.
    • The statistical analysis showed that the laser treated group had a significant improvement in some objective outcomes after the treatment period and at the 3 mo follow-up, but there were no significant differences in the subjective outcomes between the groups. Irradia laser treatment may be a valuable therapy in lateral epicondylalgia, if carried out as described in this study.
  • 38. Lasers in Medicine
    • Surgery
      • Cutting tissue
      • Cauterizing bleeding vessels
    • Diagnosis
    • Imaging
    • Physical medicine and rehabilitation
      • Power is lower
      • Maximal output <1 mW
  • 39.
    • Light therapy for rehabilitation
      • Not approved by FDA
      • Specific machines cleared for specific therapeutic uses
        • Controlled clinical trials necessary
        • Temporary relief of neck and shoulder pain of musculoskeletal origin
        • Wrist and hand pain associated with carpal tunnel syndrome
        • Iliotibial band syndrome pain
    Lasers in Medicine (cont.)
  • 40. Treatment Parameters
    • Delivery technique
    • Dosage and duration
    • Tissue penetration
  • 41. Treatment Parameters: Delivery
    • Probe type
      • Single
        • Original
      • Cluster
        • Gaining popularity
        • Best for treating large areas
    • Proximity
      • Best if in contact with skin
      • Hold 1 cm off healing wounds
    • or
      • Use sterile transparent film
  • 42. Treatment Parameters: Dosage and Duration
    • Depend on three factors: average output power (fixed), time of light exposure, and treatment area
    • Dosage = (Average power × Tx time) ÷ Tx area
      • Dosage (J/cm 2 )
      • Average power = average machine output (mW)
      • Tx time = length of treatment (min)
      • Tx area = area of laser beam or area to be treated (cm 2 )
    • Because power output is fixed, formula becomes
    • Tx time = (Dosage × Tx area) ÷ Power
      • Use table to get desired dosage.
  • 43. Approximate Laser Dosages
    • Condition Dosage
    • Superficial wounds 0.5–4.0 J/cm 2
    • Trigger points 8 J/cm 2
    • Nerve root 8–24 J/cm 2
    • Tendinitis 1–3 J/point
    • Capsulitis 1 J/point
    • Epicondylitis 2–3 J/point
    • Muscle strain 1–2 J/point
    • Patellofemoral 1–2 J/point
    • Ligament strain 2–4 J/point
    • Plantar fasciitis 1–3 J/point
  • 44. Treatment Parameters: Tissue Penetration
    • Major issue with light therapy
      • Clinically effective only if light reaches target tissue with appropriate dosage
    • Penetration is function of wavelength and power
      • Wavelength is probably the most important factor.
      • But there must be a driving force.
      • Long and short nail analogy
  • 45. Treatment Parameters: Tissue Penetration (cont.)
    • Tissue penetration is only superficial
      • <5 mm with lasers
      • Even less with LED/SLD devices
      • <1 mm with most wavelengths
      • Partly accounts for difference between results of in vitro and in vivo studies
  • 46. Treatment Parameters: Tissue Penetration (cont.)
    • Skin color
      • Penetration less in darker-skinned patients
        • More light absorbed in cutaneous layers
    • Obesity
      • Decreases effects because light has to travel farther to get to target tissue
  • 47. Foundation: Light Therapy
    • Advantages
    • 1.Relatively safe
        • a. No side effects
        • b. Athermic
      • 2. Easy to use
      • 3. Cost-effective
        • a. Therapist time
        • b. Patient recovery
    • Disadvantages
    • 1. Effects of light density on eyesight
      • 2. Limited depth of penetration
  • 48. Indications & contraindications for Light Therapy
    • Indications
      • Numerous, but most unsupported
      • Supported
        • a. Activating cells into a healing mode
        • b. Wound healing
        • c. Pain relief
        • d. Increasing tensile strength of scar tissue
    • Contraindications
      • Irradiation directly into the eye
      • Irradiation of uterus during pregnancy
      • Cancer patients
      • Organ transplant patients
      • Growing children (epiphyseal plates)
  • 49. Precautions for Light Therapy
    • Precautions
      • Be cautious when applying to patients who
        • Are photosensitive
        • Suffer from epilepsy
        • Have had a recent steroid injection
        • Are taking anti-inflammatory medication
        • Have an acute infection
        • Suffer from a thyroid condition
  • 50. Application Parameters: Light Therapy
    • Application technique
    • 1. Direct contact with the skin
        • a. Except open wound
      • 2. Treat large areas with either
          • a. Cluster probe
          • b. Grid application
            • i. treating 1 cm 2 areas consecutively
          • c. Scanning technique
            • i. Criss-crossing the wound area
    • Frequency of application
      • Daily
    • Duration of therapy
      • As long a discernable progress is being made.
  • 51. Approximate Laser Dosages
    • Condition Dosage
    • Superficial wounds 0.5–4.0 J/cm 2
    • Trigger points 8 J/cm 2
    • Nerve root 8–24 J/cm 2
    • Tendinitis 1–3 J/point
    • Capsulitis 1 J/point
    • Epicondylitis 2–3 J/point
    • Muscle strain 1–2 J/point
    • Patellofemoral 1–2 J/point
    • Ligament strain 2–4 J/point
    • Plantar fasciitis 1–3 J/point
    • Reprinted with permission from Baxter GD. Therapeutic Lasers: Theory and Practice. Edinburgh, UK: Churchill Livingstone, 1994.
  • 52. Basic Recommendations for Laser Dosages (Acute)
    • Condition Dosage per Point (J) Dosage Total (J)
    • Muscle strain 3–4 25–35
    • Tendinitis 3–6 24–30
    • Ligament sprain 3–4 25–30
    • Stress fracture 7–8 25–30
    • Open wounds 0.5–1.5 *
    • Myofascial trigger point 1.0 Once
    • *Depends on size of wound.
    • Reprinted with permission from McLeod IA. Low-level laser therapy in athletic training. Athl Ther Today 2004;9:17–21.
  • 53. Basic Recommendations for Laser Dosages (Chronic)
    • Condition Dosage per Point (J) Dosage Total (J)
    • Muscle strain 5–6 35-45
    • Tendinitis 5–8 35–45
    • Ligament sprain 5–6 35–45
    • Stress fracture 8–10 35–45
    • Open wounds 1–4 *
    • Myofascial TP 1.0 Once
    • *Depends on size of wound.
    • Reprinted with permission from McLeod IA. Low-level laser therapy in athletic training. Athl Ther Today 2004;9:17–21.
  • 54. Review
    • What is the theory for how this modality works?
    • What is the energy form and wave patterns for this modality?
    • What are the main indications for this modality?
    • How are these indications physiologically affected?
    • What are the contraindications and precautions for this modality?
    • What is the application technique for this modality?

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