Prof.Dr. Gehan MosaadProf.Dr. Gehan Mosaad

At the end of the lecture the student At the end of the lecture the student should be able toshould be able to1.1. Know classification of IRR.Know classification of IRR.2.2. Understand the mechanism of IRR Understand the mechanism of IRR

production.production.3.3. Identify and differentiate between the Identify and differentiate between the

different sources of IRR.different sources of IRR.4.4. Discus the physiological effects of Discus the physiological effects of

IRR.IRR.5.5. Determine indications and Determine indications and

contraindications of IRR.contraindications of IRR.

Infrared RadiationsInfrared Radiations Infrared radiations (IRR) are electromagnetic Infrared radiations (IRR) are electromagnetic

radiation that lies within that part of radiation that lies within that part of electromagnetic spectrum between visible light electromagnetic spectrum between visible light and microwave radiation.and microwave radiation.

The radiation is characterized by wavelength The radiation is characterized by wavelength extended fromextended from 760 760 nm to nm to 11 mm. mm.

IRR can be subdivided into 3 regions (A,B &C) IRR can be subdivided into 3 regions (A,B &C) according to their absorption and their effect according to their absorption and their effect upon the tissue.upon the tissue.

760nm to 1 mm

Classification of infrared Classification of infrared radiationradiation

TypeWavelengthPenetration

IRA(short or near IR)

760 - 1400 nm

5 mm reach to dermis

IRB(long or far IR)

1400 – 3000 nm

Up to 1 mm to epidermis

IRC3000nm – 1 mm

Not used therapeutically

Production of InfraredProduction of Infrared Infrared is produced as a result of Infrared is produced as a result of molecular molecular

motionmotion within heated materials. All within heated materials. All hot hot bodies emit bodies emit IR, IR, as increase the temperature as increase the temperature of any material aboveof any material above absolute zeroabsolute zero result in result in vibration and rotation of molecule vibration and rotation of molecule within the material .within the material .

The The wavelengthwavelength of the emitted IR are of the emitted IR are determined by the determined by the temperaturetemperature of the of the material. The higher the temperature of the material. The higher the temperature of the body, the higher the frequency, and the body, the higher the frequency, and the shorter the wavelength.shorter the wavelength.

Sources of InfraredSources of Infrared Natural sourcesNatural sources:: The sun The sun Artificial sources: Artificial sources:

1- Luminous sources 1- Luminous sources 2- Non-luminous sources2- Non-luminous sources

Artificial sourcesArtificial sources

Luminous sourcesLuminous sources Electrically heated filament made of Electrically heated filament made of

tungsten filament within a glass bulb tungsten filament within a glass bulb which contain an inert gas at low which contain an inert gas at low pressure. Part of the glass bulb is pressure. Part of the glass bulb is silvered to provide a reflector.silvered to provide a reflector.

Luminous sources emit mainly:Luminous sources emit mainly: - Short or near IR (IRA) - Visible light - Ultraviolet

Non-luminous sourcesNon-luminous sources Non-luminous sources are those which Non-luminous sources are those which

produce infrared radiation from a non-produce infrared radiation from a non-glowing source, such glowing source, such as moist heat as moist heat packspacks and non-luminous IR lamps and non-luminous IR lamps

Non-luminous infrared lamp consists Non-luminous infrared lamp consists of a coiled resistance wire which of a coiled resistance wire which embedded within a ceramic insulating embedded within a ceramic insulating materialmaterial

Non - luminous sources emit mainlyNon - luminous sources emit mainly

long long or or farfar IR radiation. IR radiation.

Absorption and penetration of IRRAbsorption and penetration of IRR

IRR is strongly absorbed near the skin IRR is strongly absorbed near the skin surface and the heat is carried to deeper surface and the heat is carried to deeper tissues by tissues by conductionconduction and by the circulating and by the circulating fluids.fluids.

The absorption and penetration of IRR rays The absorption and penetration of IRR rays depend on:depend on:

1- Wavelength of the rays1- Wavelength of the rays

2- Angle of incidence of the rays.2- Angle of incidence of the rays.

3- The intensity of the emitting source.3- The intensity of the emitting source.

4-The distance of the radiating source from the 4-The distance of the radiating source from the tissuetissue..

Physiological Effects of InfraredPhysiological Effects of Infrared

IRR is considered as superficial IRR is considered as superficial heating modalityheating modality

Cutaneous vasodilatation

Increase metabolism

Neurological effect (Pain control)

Effect on connective tissue

1 -Cutaneous vasodilatation

Heating with IRR leads to vasodilatation Heating with IRR leads to vasodilatation of the blood vessels as a result of:of the blood vessels as a result of:

release of chemical mediator histamine release of chemical mediator histamine like substance like substance

axon reflex mechanism.axon reflex mechanism.

Vasodilatation causes increase blood Vasodilatation causes increase blood flow in the cutaneous circulationflow in the cutaneous circulation

Vasodilatation Vasodilatation starts after short period of starts after short period of exposure to IRR and leads to redness of exposure to IRR and leads to redness of the skin that appears the skin that appears as irregular patchy as irregular patchy erythema erythema and its intensity depends on the and its intensity depends on the degree of heating.degree of heating.

This local This local erythemaerythema appears appears immediatelyimmediately after exposure to IRR and after exposure to IRR and lasts 30 minutes lasts 30 minutes after treatment has stopped.after treatment has stopped.

2-Increase metabolismIncrease temperature by IRR leads to Increase temperature by IRR leads to

increase metabolic activities within the increase metabolic activities within the superficial tissue due to direct effect of superficial tissue due to direct effect of heat on chemical process in the cellheat on chemical process in the cell

Increase metabolic activities lead to Increase metabolic activities lead to improve cell function and improve tissue improve cell function and improve tissue healing.healing.

3 -Neurological effect

The heat production by IRR leads to relief The heat production by IRR leads to relief pain by:pain by:

Stimulation of sensory nerves (Stimulation of sensory nerves (A-Beta nerve A-Beta nerve fibersfibers) lead to inhibition of pain at the level ) lead to inhibition of pain at the level of the spinal cord.of the spinal cord.

Decrease activity of muscle spindle leading Decrease activity of muscle spindle leading to relaxation of muscle to relaxation of muscle

Removal of waste products as the result of Removal of waste products as the result of improving circulation and increase venous improving circulation and increase venous return thus removing the source of pain return thus removing the source of pain stimulation. stimulation.

Effect on connective tissue The The heatheat effect of IR leads to increase the effect of IR leads to increase the

extensibility of connective tissue and extensibility of connective tissue and therefore is used prior to exercise to therefore is used prior to exercise to increase range of motionincrease range of motion (stretching and (stretching and mobilization exercises).mobilization exercises).

N.B.N.B. Increasing tissue extensibility by heating

through IRR will not decrease soft tissue shortening. So infrared must be used in conjunction with stretching and ROM exercises.

Therapeutic Uses of InfraredTherapeutic Uses of Infrared PainPain Muscle spasmMuscle spasm Incisional wound (Acceleration of Incisional wound (Acceleration of

healing)healing) Subacute and chronic inflammation of Subacute and chronic inflammation of

musculoskeletal systemmusculoskeletal system Chronic mild to moderate edema Chronic mild to moderate edema Prior to stretching &mobilizing Prior to stretching &mobilizing

exercisesexercises Some skin conditions (fungal infection)Some skin conditions (fungal infection)

ContraindicationsContraindications1.1. Acute inflammationAcute inflammation2.2. Acute infectionAcute infection3.3. Open woundsOpen wounds4.4. Impaired sensationImpaired sensation5.5. Impaired circulationImpaired circulation6.6. Over pregnant uterusOver pregnant uterus7.7. EyesEyes8.8. Metal Metal

Hazards and DangersHazards and Dangers

Burns: Burns: The main danger of IR treatment is The main danger of IR treatment is the burn. It occurs ifthe burn. It occurs if

1- heat is too intense.1- heat is too intense.2- the patient is not fully aware of the level of 2- the patient is not fully aware of the level of

heating. heating. 3-the patient is unable to communicate with 3-the patient is unable to communicate with

physiotherapist.physiotherapist.

Eye damage :Eye damage : The eye should be covered The eye should be covered with a light towel or head turned away during with a light towel or head turned away during the application of IRR to avoid eye surface the application of IRR to avoid eye surface dryness or possible irritation.dryness or possible irritation.