Light TherapyLight Therapy

With adaptations from With adaptations from Therapeutic Therapeutic Modalities: Art & ScienceModalities: Art & Science, Knight , Knight

& Draper (2008) for KIN 195& Draper (2008) for KIN 195

Light TherapyLight TherapyAlso called phototherapyAlso called phototherapy

Application of light from a variety of devices for a Application of light from a variety of devices for a variety of therapeutic purposesvariety of therapeutic purposes

Devices includeDevices include– Lasers Lasers – Light-emitting diodes (LEDs) Light-emitting diodes (LEDs) – Super-luminous diodes (SLDs) Super-luminous diodes (SLDs) – Fluorescent lamps Fluorescent lamps – Infrared lamps Infrared lamps – Ultraviolet lamps Ultraviolet lamps – Diachronic lampsDiachronic lamps

Confusion: Many NamesConfusion: Many NamesTerms and acronyms used to describe light therapyTerms and acronyms used to describe light therapy

– Phototherapy Phototherapy – Cold laser Cold laser – Soft laser Soft laser – Low-energy laser Low-energy laser – Low level-laser therapy (LLLT),Low level-laser therapy (LLLT),– Low-energy laser therapy (LELT) Low-energy laser therapy (LELT) – Low-intensity laser activated biostimulation (LILAB)Low-intensity laser activated biostimulation (LILAB)– Low-power laser irradiation (LPLI) Low-power laser irradiation (LPLI) – Low-power laser therapy (LPLT) Low-power laser therapy (LPLT) – Low-intensity laser (LIL) Low-intensity laser (LIL) – Monochromic infrared energyMonochromic infrared energy

Began with lasers in 1970s Began with lasers in 1970s – Acronym for light amplification by stimulated Acronym for light amplification by stimulated

emission of radiation emission of radiation – Transforms electromagnetic energyTransforms electromagnetic energy

(in or near the range of visible light) into(in or near the range of visible light) intoExtremely intense, small, nearly nondivergent beam Extremely intense, small, nearly nondivergent beam

Monochromatic radiation Monochromatic radiation

All waves in phase All waves in phase

Light Therapy: HistoryLight Therapy: History

Lasers and LEDs/SLDsLasers and LEDs/SLDs

LEDLED– Special type of semiconductor diode that emits visible Special type of semiconductor diode that emits visible

light when electric current passes through itlight when electric current passes through it

SLDSLD– A brighter LEDA brighter LED

Both lasers and LED/SLDs deliver light of specific Both lasers and LED/SLDs deliver light of specific wavelengthwavelength– But light is generated differentlyBut light is generated differently– Some characteristics differentSome characteristics different

No consensus about relative merits of these two No consensus about relative merits of these two technologiestechnologies– So difficult to discuss their therapeutic value So difficult to discuss their therapeutic value – Major problem is with terminology. Major problem is with terminology.

LEDs and SLDs (cont.)LEDs and SLDs (cont.)

However, light is monochromatic and not However, light is monochromatic and not coherentcoherent– More scattered than laserMore scattered than laser– Less will strike targetLess will strike target– Less energy imparted to targetLess energy imparted to target

Laser Light vs. Normal LightLaser Light vs. Normal Light

Very differentVery different

Laser lightLaser light Normal lightNormal light– MonophasicMonophasic MultiphasicMultiphasic– MonochromaticMonochromatic MultichromaticMultichromatic– Coherent Coherent IncoherentIncoherent– Nondivergent Nondivergent Divergent Divergent

(directional)(directional)

That is . . . That is . . .

Laser Light vs. Normal Light Laser Light vs. Normal Light (cont.)(cont.)

An LED emits light with waves of the same An LED emits light with waves of the same frequency (monochromatic) but out of frequency (monochromatic) but out of phase (incoherent)phase (incoherent)

Laser Light vs. Normal Light Laser Light vs. Normal Light (cont.)(cont.)

A laser emits light with waves of the same A laser emits light with waves of the same frequency (monochromatic) and in phase frequency (monochromatic) and in phase (coherent).(coherent).

Laser Light TerminologyLaser Light Terminology

Light Light – Electromagnetic radiation that produces a visual Electromagnetic radiation that produces a visual

sensationsensation

AmplifyAmplify– Increase in size, volume, or significanceIncrease in size, volume, or significance

StimulateStimulate– To excite or invigorate To excite or invigorate – To encourage or provoke something to grow, To encourage or provoke something to grow,

develop, or become more activedevelop, or become more active

Laser Light Terminology (cont.)Laser Light Terminology (cont.)

EmissionEmission– A flowing forth, such as the release of A flowing forth, such as the release of

electrons from parent atomselectrons from parent atoms

RadiationRadiation– Energy transmitted as rays, waves, or Energy transmitted as rays, waves, or

particlesparticles

Laser Light Terminology (cont.)Laser Light Terminology (cont.)

Nondivergent Nondivergent – Incapable of Incapable of

separating or separating or wideningwidening

– Contrast the light Contrast the light from a laser pointer from a laser pointer (nondivergent) with (nondivergent) with that coming from a that coming from a flashlight flashlight (divergent).(divergent).

Laser DevicesLaser Devices

Many, each with a specific frequency, Many, each with a specific frequency, amplification, and beam focusamplification, and beam focus

Not interchangeableNot interchangeable– Can’t treat wounds with TV tunerCan’t treat wounds with TV tuner

Laser Energy Production Laser Energy Production

External energy is applied to medium. External energy is applied to medium.

Laser Energy Production (cont.)Laser Energy Production (cont.)

Causes spontaneous release of photons, Causes spontaneous release of photons, some of which (P6) reflect back and forth some of which (P6) reflect back and forth between the two mirrors between the two mirrors

Laser Energy Production (cont.)Laser Energy Production (cont.)

Leads to intense photon resonance, part of Leads to intense photon resonance, part of which is released as laser light through the which is released as laser light through the half-slivered mirror. half-slivered mirror.

Laser ClassificationLaser Classification

Classified by lasing medium and safetyClassified by lasing medium and safety– Often referred to by colorOften referred to by color

ImpreciseImprecise– For example, UV includes waves of 150–380 nm For example, UV includes waves of 150–380 nm – But response to 150 nm waves different from that to 380 But response to 150 nm waves different from that to 380

nm wavesnm waves

– Avoid this practice.Avoid this practice.

Gas Gas – Helium and helium neon (HeNe) most commonHelium and helium neon (HeNe) most common

Diode or semiconductor Diode or semiconductor – Either small and low powered or large and high poweredEither small and low powered or large and high powered– Low powerLow power

Laser pointers, laser printers, and compact disc players Laser pointers, laser printers, and compact disc players

780 nm aluminum gallium arsenide (AlGaAs) laser diode used in CD 780 nm aluminum gallium arsenide (AlGaAs) laser diode used in CD players is most common type of laserplayers is most common type of laser

– Large industrial diode lasers can generate great amounts of Large industrial diode lasers can generate great amounts of heatheat

Used for cutting and weldingUsed for cutting and welding

Laser Classification by Medium Laser Classification by Medium

DyeDye– Uses large-molecule organic dyes in a liquid Uses large-molecule organic dyes in a liquid

solutionsolution

– Can be tuned to produce broad range of Can be tuned to produce broad range of wavelengthswavelengths

Solid stateSolid state– Uses various mineralsUses various minerals

– ExamplesExamplesRuby, neodymium:yttrium-aluminum-garnet (YAG) Ruby, neodymium:yttrium-aluminum-garnet (YAG) laserslasers

Laser Classification by Medium Laser Classification by Medium (cont.)(cont.)

Laser Classification by Medium Laser Classification by Medium (cont.)(cont.)

TypeType MediumMedium Wavelength (nm)Wavelength (nm) SafetySafety GasGas HeNe HeNe 633 633 I–IV I–IV

GasGas CO2 CO2 10,600 10,600 IIIb–IV IIIb–IV

GasGas Argon Argon 488–514 488–514 IV IV

Diode* Diode* AlGaAs AlGaAs 600–1000 600–1000 IIIb IIIb

DyeDye Tunable dye 577 Tunable dye 577 IV IV

Solid state RubySolid state Ruby 694 694 IV IV

Solid state HdYagSolid state HdYag 1060 1060 IV IV

ExcimerExcimer Dimer Dimer 351 351 IV IV

* Semiconductor.

Laser Classification by Safety Laser Classification by Safety (cont.)(cont.)

PowerPower

ClassClass (mW)(mW) VisibleVisible Safety ConcernsSafety Concerns

II <0.5<0.5 Either* None Either* None

IIII <1 <1 Visible Safe for momentary viewing; Visible Safe for momentary viewing;

IIIaIIIa <5<5 Either Photochemical effect Either Photochemical effect

IIIbIIIb <500<500 Either Photobiomodulation, Either Photobiomodulation, no photothermal effect, no photothermal effect,

no harm to skin or clothing, no harm to skin or clothing, potential damage to eye potential damage to eye

IVIV >500>500 Either Photothermal effect, Either Photothermal effect, harmful to skin, eyes, andharmful to skin, eyes, and

clothing, use with extreme cautionclothing, use with extreme caution*Either, both visible and nonvisible.

Tissue Penetration of Various Tissue Penetration of Various WavelengthsWavelengths

Wavelength (nm)Wavelength (nm) Color RangeColor Range Penetration (mm)Penetration (mm)

150–380150–380 UVUV <0.1<0.1

390–470390–470 Violet to deep blueViolet to deep blue ~0.3~0.3

475–545475–545 Blue to greenBlue to green ~0.3–0.5~0.3–0.5

545–600545–600 Yellow to orangeYellow to orange ~0.5–1.0~0.5–1.0

600–650 600–650 RedRed ~1.0–2.0~1.0–2.0

650–1,000 650–1,000 Deep red to IRDeep red to IR22 0–3.00–3.0

1,000–1,350 1,000–1,350 Near to mid-IRNear to mid-IR33 0–5.00–5.0

1,350–12,000 1,350–12,000 IRIR <0.1<0.1

Johnson D. Defining “The Specs” of Phototherapy Devices. Johnson D. Defining “The Specs” of Phototherapy Devices. NATA NATA NewsNews; 2007. 10:16-18.; 2007. 10:16-18.

When absorbed, specific wavelengths of When absorbed, specific wavelengths of laser light cause specific physiological laser light cause specific physiological responses.responses.

Therapeutic value of responses debated.Therapeutic value of responses debated.– Industry continues to growIndustry continues to grow

Now using nonlaser devicesNow using nonlaser devices– LEDs, SLDs, polarized polychromic light LEDs, SLDs, polarized polychromic light – Deliver light of specific wavelength to bodyDeliver light of specific wavelength to body

Laser TheoryLaser Theory

PhotobiomodulationPhotobiomodulation

Act of modifying biological processes with Act of modifying biological processes with lightlight– Stimulate or inhibit molecules or structuresStimulate or inhibit molecules or structures– Modify healing and painModify healing and pain

Photobiomodulation (cont.)Photobiomodulation (cont.)

– Following occur in tissue cultures (not Following occur in tissue cultures (not confirmed by clinical trials)confirmed by clinical trials)

Photobiomodulation of cellular eventsPhotobiomodulation of cellular events

Stimulated/optimized tissue repairStimulated/optimized tissue repair

Pain reliefPain relief

UV RadiationUV Radiation

A portion of electromagnetic spectrum that A portion of electromagnetic spectrum that produces chemical reactions in produces chemical reactions in microorganisms, epidermis, and dermismicroorganisms, epidermis, and dermisEffects are superficial and mainly chemicalEffects are superficial and mainly chemicalUsed therapeutically to destroy superficial Used therapeutically to destroy superficial infectious organisms and other infectious organisms and other microorganismsmicroorganismsEasy to misuseEasy to misuse

UV Radiation (cont.)UV Radiation (cont.)

Incorrect application may cause dermatitisIncorrect application may cause dermatitis• Local ulceration Local ulceration • Impetigo Impetigo • Folliculitis Folliculitis

• Herpes simplexHerpes simplex

Overexposure can lead toOverexposure can lead to• Increased sensitivity to ordinary sunlightIncreased sensitivity to ordinary sunlight• CancerCancer

Generally used by dermatologistsGenerally used by dermatologistsRarely by athletic trainers or physical therapistsRarely by athletic trainers or physical therapists

Proposed mechanism of light therapy (Enwemeka & Proposed mechanism of light therapy (Enwemeka & PPööntinen, 2005)ntinen, 2005)

Light therapy research findingsLight therapy research findings

Robert A. de Bie , Henrica C. W. de Vet, Ton F. Robert A. de Bie , Henrica C. W. de Vet, Ton F. Lenssen, Frans A. J. M. van den Wildenberg, Lenssen, Frans A. J. M. van den Wildenberg, Gauke Kootstra and Paul G. Knipschild.Gauke Kootstra and Paul G. Knipschild. Low-Low-level laser therapy in ankle sprains: A level laser therapy in ankle sprains: A randomized clinical trial. randomized clinical trial. Archives of Physical Archives of Physical Medicine and RehabilitationMedicine and Rehabilitation (1998) 79: 1415- (1998) 79: 1415-1420.1420.

Conclusions:Conclusions: Neither high- nor low-dose laser Neither high- nor low-dose laser therapy is effective in the treatment of lateral therapy is effective in the treatment of lateral ankle sprains. accepted 28 April 1998. ankle sprains. accepted 28 April 1998. 

Light therapy research findings, cont.Light therapy research findings, cont.

Arne Nyholm Gam, Hanne Thorsen and Arne Nyholm Gam, Hanne Thorsen and Frank Lønnberg.Frank Lønnberg. The effect of low-level The effect of low-level laser therapy on musculoskeletal pain: A laser therapy on musculoskeletal pain: A meta-analysis. meta-analysis. PainPain (1993) 52: 63-66. (1993) 52: 63-66.

We conclude that Low Level Laser We conclude that Low Level Laser Therapy has no effect on pain in Therapy has no effect on pain in musculoskeletal syndromes.musculoskeletal syndromes.

Jeffrey R. Basford,Jeffrey R. Basford, Gerard A. Malanga, David A. Krause, and William S. Gerard A. Malanga, David A. Krause, and William S.

Harmsen.Harmsen. A randomized controlled evaluation of low-intensity laser A randomized controlled evaluation of low-intensity laser therapy: Plantar fasciitis. Archives of Physical Medicine and therapy: Plantar fasciitis. Archives of Physical Medicine and

Rehabilitation; (1998) 79: 249-254.Rehabilitation; (1998) 79: 249-254.

Subjects: Thirty-two otherwise healthy individuals with plantar Subjects: Thirty-two otherwise healthy individuals with plantar fasciitis of more than 1 month's duration.fasciitis of more than 1 month's duration.Intervention: Dummy or active irradiation with a 30mW .83μm Intervention: Dummy or active irradiation with a 30mW .83μm GaAlAs continuous-wave infrared (IR) diode laser three times a GaAlAs continuous-wave infrared (IR) diode laser three times a week for 4 weeks.week for 4 weeks.Measurements: Morning pain, pain with toe walking, tenderness to Measurements: Morning pain, pain with toe walking, tenderness to palpation, …palpation, …Results: No significant differences were found between the groups Results: No significant differences were found between the groups in any of the outcome measures either during treatment or at the 1-in any of the outcome measures either during treatment or at the 1-month follow-up. Treatment, however, was well tolerated and side month follow-up. Treatment, however, was well tolerated and side effects were minimal.effects were minimal.

Conclusions: Low-intensity IR laser therapy appears safe Conclusions: Low-intensity IR laser therapy appears safe but, at least within the parameters of this study, is not but, at least within the parameters of this study, is not beneficial in the treatment of plantar fasciitis.beneficial in the treatment of plantar fasciitis.

TT Karu. Primary and secondary mechanisms of action of visible to near-IR Karu. Primary and secondary mechanisms of action of visible to near-IR radiation on cells. radiation on cells. Journal of Photochemistry and Photobiology B: Journal of Photochemistry and Photobiology B: BiologyBiology,  (March 1999) Volume 49, Issue 1, Pages 1-17.,  (March 1999) Volume 49, Issue 1, Pages 1-17.

JR. Basford, CG. Sheffield, KR. CieslakJR. Basford, CG. Sheffield, KR. Cieslak Laser therapy: A randomized, controlled Laser therapy: A randomized, controlled trial trial of the effects of low intensity Nd:YAG laser irradiation of the effects of low intensity Nd:YAG laser irradiation on lateral epicondylitis.on lateral epicondylitis. Archives of Physical Medicine and Archives of Physical Medicine and RehabilitationRehabilitation (November 2000) Volume (November 2000) Volume 81, Issue 11, Pages 1504-1510.81, Issue 11, Pages 1504-1510.

Treatment with low intensity 1.06-μm laser Treatment with low intensity 1.06-μm laser irradiation within the parameters of this irradiation within the parameters of this study was a safe but ineffective treatment of study was a safe but ineffective treatment of lateral epicondylitis.lateral epicondylitis. All underwent irradiation for 60 seconds at 7 points along All underwent irradiation for 60 seconds at 7 points along the symptomatic forearm 3 times weekly for 4 weeks by the symptomatic forearm 3 times weekly for 4 weeks by a masked therapist. The sole difference between the a masked therapist. The sole difference between the groups was that the probe of a 1.06-μm continuous wave groups was that the probe of a 1.06-μm continuous wave laser emitted 204mW/cm2 (12.24J/cm2) for the treated laser emitted 204mW/cm2 (12.24J/cm2) for the treated subjects and was inactive for the control subjects. subjects and was inactive for the control subjects. Subjects were assessed at the beginning, midpoint Subjects were assessed at the beginning, midpoint (session 6), and end (session 12) of treatment, as well (session 6), and end (session 12) of treatment, as well as at follow-up 28 to 35 days after their last treatment.as at follow-up 28 to 35 days after their last treatment.

JR. Basford, CG. Sheffield, WS. Harmsen. Laser therapy: A randomized, controlled JR. Basford, CG. Sheffield, WS. Harmsen. Laser therapy: A randomized, controlled trial of the effects of low-intensity Nd:YAG laser irradiation on trial of the effects of low-intensity Nd:YAG laser irradiation on

musculoskeletal back pain. musculoskeletal back pain. Archives of Physical Medicine and RehabilitationArchives of Physical Medicine and Rehabilitation (June 1999): Volume 80, Issue 6, Pages 647-652.(June 1999): Volume 80, Issue 6, Pages 647-652.

Treatment with low-intensity 1.06μm laser irradiation Treatment with low-intensity 1.06μm laser irradiation produced a moderate reduction in pain and produced a moderate reduction in pain and improvement in function in patients with improvement in function in patients with musculoskeletal low back pain. Benefits, however, musculoskeletal low back pain. Benefits, however, were limited and decreased with time. Further were limited and decreased with time. Further research is warranted.research is warranted.All underwent irradiation for 90 seconds at eight symmetric points All underwent irradiation for 90 seconds at eight symmetric points along the lumbosacral spine three times a week for 4 weeks by a along the lumbosacral spine three times a week for 4 weeks by a masked therapist. The sole difference between the groups was that masked therapist. The sole difference between the groups was that the probes of a 1.06μm neodymium: yttrium-aluminum-garnet laser the probes of a 1.06μm neodymium: yttrium-aluminum-garnet laser emitted 542mW/cm2 for the treated subjects and were inactive for emitted 542mW/cm2 for the treated subjects and were inactive for the control subjectsthe control subjects

MA. Naeser, KK. Hahn, BE. Lieberman, KF. Branco. Carpal tunnel syndrome pain MA. Naeser, KK. Hahn, BE. Lieberman, KF. Branco. Carpal tunnel syndrome pain treated with low-level laser and microamperes transcutaneous electric treated with low-level laser and microamperes transcutaneous electric

nerve stimulation: A controlled study. nerve stimulation: A controlled study. Archives of Physical Medicine and Archives of Physical Medicine and RehabilitationRehabilitation (July 2002): Volume 83, Issue 7, Pages 978-988. (July 2002): Volume 83, Issue 7, Pages 978-988.

Significant decreases in McGill Pain Significant decreases in McGill Pain Questionnaire score, median nerve sensory Questionnaire score, median nerve sensory latency, and Phalen and Tinel signs after the latency, and Phalen and Tinel signs after the real treatment series but not after the sham real treatment series but not after the sham treatment series.treatment series. Patients could perform their previous work (computer Patients could perform their previous work (computer

typist, handyman) and were stable for 1 to 3 years.typist, handyman) and were stable for 1 to 3 years.

E Haker, T Lundeberg. Is low-energy laser treatment effective in lateral E Haker, T Lundeberg. Is low-energy laser treatment effective in lateral epiconylagia? epiconylagia? Journal of Pain and Symptom ManagementJournal of Pain and Symptom Management (May (May 1991);Volume 6, Issue 4,  Pages 241-2461991);Volume 6, Issue 4,  Pages 241-246..

Forty-nine patients were consecutively assigned at random to two groups, Forty-nine patients were consecutively assigned at random to two groups, laser or placebo. The Mid 1500 Irradia laser was used with the following laser or placebo. The Mid 1500 Irradia laser was used with the following parameters: wavelength 904 nm; average power output 12 mW; peak value 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 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 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 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. mm2. Patients were treated 2–3 times weekly, for a total of 10 treatments. Follow-ups were done after three and 12 mo. Follow-ups were done after three and 12 mo.

The statistical analysis showed that the laser treated The statistical analysis showed that the laser treated group had a significant improvement in some group had a significant improvement in some objective outcomes after the treatment period and at objective outcomes after the treatment period and at the 3 mo follow-up, but there were no significant the 3 mo follow-up, but there were no significant differences in the subjective outcomes between the differences in the subjective outcomes between the groups. Irradia laser treatment may be a valuable groups. Irradia laser treatment may be a valuable therapy in lateral epicondylalgia, if carried out as therapy in lateral epicondylalgia, if carried out as described in this study.described in this study.

Lasers in MedicineLasers in Medicine

SurgerySurgery– Cutting tissueCutting tissue– Cauterizing bleeding vessels Cauterizing bleeding vessels

Diagnosis Diagnosis

Imaging Imaging

Physical medicine and rehabilitationPhysical medicine and rehabilitation– Power is lowerPower is lower– Maximal output <1 mWMaximal output <1 mW

Light therapy for rehabilitationLight therapy for rehabilitation– Not approved by FDANot approved by FDA– Specific machines cleared for specific Specific machines cleared for specific

therapeutic usestherapeutic usesControlled clinical trials necessaryControlled clinical trials necessary

Temporary relief of neck and shoulder pain of Temporary relief of neck and shoulder pain of musculoskeletal origin musculoskeletal origin

Wrist and hand pain associated with carpal Wrist and hand pain associated with carpal tunnel syndrometunnel syndrome

Iliotibial band syndrome painIliotibial band syndrome pain

Lasers in Medicine (cont.)Lasers in Medicine (cont.)

Treatment ParametersTreatment Parameters

Delivery techniqueDelivery technique

Dosage and durationDosage and duration

Tissue penetrationTissue penetration

Treatment Parameters:Treatment Parameters:DeliveryDelivery

Probe typeProbe type– SingleSingle

OriginalOriginal

– ClusterClusterGaining popularityGaining popularityBest for treating large areasBest for treating large areas

ProximityProximity– Best if in contact with skinBest if in contact with skin– Hold 1 cm off healing woundsHold 1 cm off healing wounds

oror– Use sterile transparent filmUse sterile transparent film

Treatment Parameters:Treatment Parameters:Dosage and Duration Dosage and Duration

Depend on three factors: average output power (fixed), Depend on three factors: average output power (fixed), time of light exposure, and treatment areatime of light exposure, and treatment area

Dosage = (Average power × Tx time) ÷ Tx areaDosage = (Average power × Tx time) ÷ Tx area– Dosage (J/cmDosage (J/cm22) ) – Average power = average machine output (mW)Average power = average machine output (mW)– Tx time = length of treatment (min)Tx time = length of treatment (min)– Tx area = area of laser beam or area to be treated (cmTx area = area of laser beam or area to be treated (cm22))

Because power output is fixed, formula becomesBecause power output is fixed, formula becomesTx time = (Dosage × Tx area) ÷ PowerTx time = (Dosage × Tx area) ÷ Power

– Use table to get desired dosage.Use table to get desired dosage.

Approximate Laser DosagesApproximate Laser DosagesConditionCondition DosageDosageSuperficial woundsSuperficial wounds 0.5–4.0 J/cm0.5–4.0 J/cm22

Trigger pointsTrigger points 8 J/cm8 J/cm22

Nerve rootNerve root 8–24 J/cm8–24 J/cm22

TendinitisTendinitis 1–3 J/point1–3 J/point

CapsulitisCapsulitis 1 J/point1 J/point

EpicondylitisEpicondylitis 2–3 J/point2–3 J/point

Muscle strainMuscle strain 1–2 J/point1–2 J/point

Patellofemoral Patellofemoral 1–2 J/point1–2 J/point

Ligament strainLigament strain 2–4 J/point2–4 J/point

Plantar fasciitisPlantar fasciitis 1–3 J/point1–3 J/point

Treatment Parameters:Treatment Parameters:Tissue PenetrationTissue Penetration

Major issue with light therapyMajor issue with light therapy– Clinically effective only if light reaches target tissue Clinically effective only if light reaches target tissue

with appropriate dosagewith appropriate dosage

Penetration is function of wavelength and Penetration is function of wavelength and powerpower– Wavelength is probably the most important factor.Wavelength is probably the most important factor.– But there must be a driving force.But there must be a driving force.– Long and short nail analogyLong and short nail analogy

Treatment Parameters:Treatment Parameters:Tissue Penetration (cont.)Tissue Penetration (cont.)

Tissue penetration is only superficialTissue penetration is only superficial– <5 mm with lasers<5 mm with lasers– Even less with LED/SLD devicesEven less with LED/SLD devices– <1 mm with most wavelengths <1 mm with most wavelengths – Partly accounts for difference between Partly accounts for difference between

results of in vitro and in vivo studies results of in vitro and in vivo studies

Treatment Parameters:Treatment Parameters:Tissue Penetration (cont.)Tissue Penetration (cont.)

Skin colorSkin color– Penetration less in darker-skinned patients Penetration less in darker-skinned patients

More light absorbed in cutaneous layersMore light absorbed in cutaneous layers

ObesityObesity– Decreases effects because light has to Decreases effects because light has to

travel farther to get to target tissuetravel farther to get to target tissue

Foundation: Light Therapy Foundation: Light Therapy

AdvantagesAdvantages 1.Relatively safe1.Relatively safe

a. No side effectsa. No side effectsb. Athermicb. Athermic

2. Easy to use2. Easy to use3. Cost-effective 3. Cost-effective

a. Therapist timea. Therapist timeb. Patient recoveryb. Patient recovery

DisadvantagesDisadvantages1. Effects of light density on eyesight1. Effects of light density on eyesight

2. Limited depth of penetration2. Limited depth of penetration

Indications & contraindications Indications & contraindications for Light Therapyfor Light Therapy

IndicationsIndications1.1. Numerous, but most Numerous, but most

unsupportedunsupported

2.2. Supported Supported a. Activating cells into a a. Activating cells into a

healing modehealing mode

b. Wound healingb. Wound healing

c. Pain reliefc. Pain relief

d. Increasing tensile d. Increasing tensile strength of scar strength of scar tissuetissue

ContraindicationsContraindications1.1. Irradiation directly Irradiation directly

into the eyeinto the eye

2.2. Irradiation of uterus Irradiation of uterus during pregnancy during pregnancy

3.3. Cancer patientsCancer patients

4.4. Organ transplant Organ transplant patientspatients

5.5. Growing children Growing children (epiphyseal plates)(epiphyseal plates)

Precautions for Light Therapy Precautions for Light Therapy

PrecautionsPrecautions1.1. Be cautious when applying to patients whoBe cautious when applying to patients who

a.a. Are photosensitiveAre photosensitive

b.b. Suffer from epilepsySuffer from epilepsy

c.c. Have had a recent steroid injectionHave had a recent steroid injection

d.d. Are taking anti-inflammatory medicationAre taking anti-inflammatory medication

e.e. Have an acute infectionHave an acute infection

f.f. Suffer from a thyroid conditionSuffer from a thyroid condition

Application Parameters: Application Parameters: Light Light Therapy Therapy

Application techniqueApplication technique1. 1. Direct contact with the skinDirect contact with the skin

a. Except open wounda. Except open wound 2. Treat large areas with either2. Treat large areas with either

a. Cluster probea. Cluster probeb. Grid applicationb. Grid application

i. treating 1 cmi. treating 1 cm22 areas consecutively areas consecutivelyc. Scanning techniquec. Scanning technique

i. Criss-crossing the wound areai. Criss-crossing the wound area

Frequency of applicationFrequency of application1.1. DailyDaily

Duration of therapyDuration of therapy1.1. As long a discernable progress is being made.As long a discernable progress is being made.

Approximate Laser DosagesApproximate Laser DosagesConditionCondition DosageDosageSuperficial woundsSuperficial wounds 0.5–4.0 J/cm0.5–4.0 J/cm22

Trigger pointsTrigger points 8 J/cm8 J/cm22

Nerve rootNerve root 8–24 J/cm8–24 J/cm22

TendinitisTendinitis 1–3 J/point1–3 J/point

CapsulitisCapsulitis 1 J/point1 J/point

EpicondylitisEpicondylitis 2–3 J/point2–3 J/point

Muscle strainMuscle strain 1–2 J/point1–2 J/point

Patellofemoral Patellofemoral 1–2 J/point1–2 J/point

Ligament strainLigament strain 2–4 J/point2–4 J/point

Plantar fasciitisPlantar fasciitis 1–3 J/point1–3 J/point

Reprinted with permission from Baxter GD. Therapeutic Lasers: Theory and Practice. Edinburgh, UK: Reprinted with permission from Baxter GD. Therapeutic Lasers: Theory and Practice. Edinburgh, UK: Churchill Livingstone, 1994. Churchill Livingstone, 1994.

Basic Recommendations for Basic Recommendations for Laser Dosages (Acute)Laser Dosages (Acute)

ConditionCondition Dosage per Point (J)Dosage per Point (J) Dosage Total (J)Dosage Total (J)Muscle strainMuscle strain 3–4 3–4 25–35 25–35

TendinitisTendinitis 3–6 3–6 24–30 24–30

Ligament sprain Ligament sprain 3–4 3–4 25–30 25–30

Stress fracture Stress fracture 7–8 7–8 25–30 25–30

Open woundsOpen wounds 0.5–1.50.5–1.5 **

Myofascial trigger point Myofascial trigger point 1.0 1.0 OnceOnce

*Depends on size of wound.*Depends on size of wound.

Reprinted with permission from McLeod IA. Low-level laser therapy in athletic Reprinted with permission from McLeod IA. Low-level laser therapy in athletic training. Athl Ther Today 2004;9:17–21. training. Athl Ther Today 2004;9:17–21.

Basic Recommendations for Laser Basic Recommendations for Laser Dosages (Chronic)Dosages (Chronic)

ConditionCondition Dosage per Point (J)Dosage per Point (J) Dosage Total (J)Dosage Total (J)

Muscle strainMuscle strain 5–6 5–6 35-45 35-45

TendinitisTendinitis 5–8 5–8 35–45 35–45

Ligament sprain Ligament sprain 5–6 5–6 35–45 35–45

Stress fracture Stress fracture 8–10 8–10 35–45 35–45

Open woundsOpen wounds 1–41–4 **

Myofascial TPMyofascial TP 1.0 1.0 OnceOnce

*Depends on size of wound.*Depends on size of wound.Reprinted with permission from McLeod IA. Low-level laser therapy in athletic training. Athl Reprinted with permission from McLeod IA. Low-level laser therapy in athletic training. Athl

Ther Today 2004;9:17–21.Ther Today 2004;9:17–21.

ReviewReview

What is the theory for how this modality works?What is the theory for how this modality works?

What is the energy form and wave patterns for this What is the energy form and wave patterns for this modality?modality?

What are the main indications for this modality?What are the main indications for this modality?

How are these indications physiologically affected?How are these indications physiologically affected?

What are the contraindications and precautions for What are the contraindications and precautions for this modality?this modality?

What is the application technique for this modality?What is the application technique for this modality?