INFRA RED

BY PT JITENDRA

INFRA RED

IR has no color, it is detected by warmth

IR is emitted from any heated body

Its wavelength is higher than visible light

IR has a wavelength of 760nm to 1mm

ELECTRO MAGNETIC SPECTRUM

INITIAL WAVES WAVELENGTH

R RADIOWAVES 0.1 MM TO 100 KM

I INFRA RED 750 NM TO 0.4 MM

V VISIBLE LIGHT 400 NM TO 750 NM

U ULTRA VIOLET 10 NM TO 400 NM

XG X-RAY / GAMMA RAYS

0.01 PM TO 100 NM

CLASSIFICATION OF IR

IR

IR A

760- 1400 NM

THERAPEUTIC

IR B

1400 – 3000 NM

THERAPEUTIC

IR C

3000NM – 1MM

NON THERAPEUTIC

Heated material produce IR radiation

Higher temperature are associate with higher frequency, & shorter wavelength

TEMP α 1 / WAVELENGTH & TEMP α FREQUENCY

If short IR is to be produced material must not be burnt by higher temperature used.

Convenient method is to heat a resistance WIRE by passing an electric current through it

Electrical heater is made up of coil of suitable resistance WIRE , i.e. nickel- chromium alloy, wound on ceramic insulator

IR LAMPS

LUMINOUS GENERATOR

NON - LUMINOUS GENERATOR

NON LUMINOUS GENERATOR (I.E. COIL HEATER)

IR source is a coil of WIRE wrapped around a cylindrical ceramic insulator

In this heaters WIRE glows red, thus giving some radiation in visible spectrum

Some IR lamps for therapy have WIRE embedded in insulation ceramic, ceramic is heated because of lamp which emits IR so that little or no visible radiation is emitted

Heater WIRE can also be mounted behind a metal plate or inside a metal tube which does not become hot spot but emits IR in same way

IR emitter is placed at focus of reflector to produce an uniform wave

If reflector is more spherical instead of convergence of beam, it will be diverge, this is usually adapted in clinic.

Reflector & emitter are mounted on a mobile metal stand which can be adjusted to alter height & angle of reflector or emitter.

When lamps are switched on they require time to warm up because of thermal inertia of mass of metal & insulating material that has to be heated

Small lamps may take about 5 min. but large ones may take up to 15 min to reach maximum emission

Lamps with an exposed coil give off a red glow although they are collectively designated as “ non-

luminous” sources

With non-luminous Exposure is in Long IR wavelength range

LUMINOUS GENERATOR (I.E. BULB)

They consist of a tungsten filament in a large glass envelope which contains inert gas at low pressure.

Part of inside of glass bulb is silvered to provide a reflector

Works on same principle as a simple electric light bulb

Filament is heated to a high temperature around 3000 by a current passed through it

So gives out continuous spectrum in IR & visible region

Oxidation(burnt) does not occur because of no oxygen, only part of inert air

Radiation extends from SHORT IR to visible light to the UVR.

UVR is absorbed in glass

Luminous generators are sometimes called RADIANT HEAT as they emit both IR & visible light

POWER

SMALL LAMPS (BOTH) 250-500 WATTLARGE, NON LUMINOUS 750-1000 WLARGE , LUMINOUS 750-1500 W

Larger lamps are used to treat extensive area , but same effect can be achieved by placing small three lamps in a row

EMISSION

NON LUMINOUS3000 – 4000 NM (LONG IR )

LUMINOUSSHORT IR 5% VISIBLE1% UVR

PENETRATION & ABSORBTION IT DEPENDS UPON:

STRUCTURE

VASCULARITY

PIGMENTATION OF SKIN

WAVELENGTH OF RADIATION

DEPTH OF PENETRATION

Depth of penetration: it is depth at which approximately 63% of radiation energy has been absorbed & 37% remains

3000 nm depth of penetration is 0.1mm

Increasing penetration with decreasing wavelength in short IR to a maximum penetration depth of 3 mm at 1000 nm

TECHNIQUE OF APPLICATION

Patient POSITION : SUITABLE, WELL SUPPORTED, WITH AREA

TO BE TREATED EXPOSED. EXPLANATION : EXPLAIN NATURE AND EFFECT OF

TREATMENT TO PATIENT EXAMINATION AND TESTING : EXAMINE THE SKIN TO

BE TREATED AND TEST THERMAL SENSATION.

APPARATUS : IF A NON – LUMINOUS LAMP IS CHOOSEN SWITCH IT

5 MIN BEFORE TREATMENT STARTS TO ALLOW A TIME TO WARM UP

LUMINOUS LAMP DOES NOT REQUIRE WARM UP TIME.

SETTING UP EXPOSE THE SKIN TO BE TREATED COVER EYE, A TOWEL IS SUFFICIENT POSITION LAMP IN SUCH A WAY THAT RAYS STRIKE AT

90 DEREE TO SKIN SET LAMP AT 60-75 CMS FOR LARGE LAMP (750 TO

1000 WATTS) SET LAMP AT 40-45 CMS FOR SMALL LAMP

INSTRUCTIONS AND WARNING ADWISE PATIENT OF REQUIRED LEVEL OF HEAT AND

IT MUST NOT BE HOT AS IT BURN. ASK PATIENT NOT TO TOUCH ANY PART OF LAMP OR

TO MOVE DURING TREATMENT ALERT THERAPIST IF IT IS MORE THAN COMFORTABLE

LEVEL OF HEATING.

APPLICATION INTENSITY IN MOST IR LAMP IS CONTROLLED BY

DISTANCE. DOUBLING THE LAMP TO SKIN DISTANCE REDUCE THE

INTENSITY (WCM-2) TO ONE QUARTER TRIPLING THE LAMP TO SKIN DISTANCE REDUCE THE

INSTENSITY TO ONE NINTH

TERMINATION AT THE END OF TREATMENT SKIN SHOULD BE

CHECKED ON PALPATION IT LOOKS MILD OR MODERATELY

WARM MODERATE ERYTHEMA SHOULD BE VISIBLE. ERYTHEMA TENDS TO VARY WITH SKIN COLOR, NOT

JUST TEMPERATURE.

PHYSIOLOGICAL EFFECT

PHYSIOLOGICAL VASODILATATIONSWEATINGSENSATIONINCREASE IN METABOLISMNEUROLOGICAL RELAXATIONDECREASE MUSCLE TONEDECREASE OEDEMADECREASE MUSCLE SPASMANALGESIA

PHYSIOLOGICAL VASODILATATION

Local cutaneous vasodilatation

due to liberation of chemical vasodilators, histamine & similar substances

Vasodilatation starts after latent period of 1-2min, it is mainly because of arteriolar

vasodilatation

With IR regular patchy appearance

Local Erythema may last up to 30 min after IR radiation has stopped

CHRONIC CHANGESDestruction of erythrocyte, releasing pigments &

causing brown discoloration of skin

THERAPEUTIC USES OF IR

PAIN RELIEFREDUCTION OF MUSCLE SPASMACCELERATION OF HEALING & REPAIRPROMOTE TISSUE EXTENSIBILITY REDUCE JOINT STIFFNESSTO REDUCE OEDEMATO PROMOTE SWEATINGAS ANTIDOTE TO UVR

CHOICE OF LUMINOUS & NON LUMINOUS LAMP

LUMINOUS HEAT LAMPElectrically heated filament in an evacuated glass bulb, with silver inner surface

Gives IR + visible rays

Produce Short IR (1000nm)

Deep heating compare to non luminous

NON LUMINOUS LAMP

Electrically heated wire embedded in ceramic and backed by reflector

Gives only IR

Produce long IR (3000-4000nm)

Superficial heating

LUMINOUS HEAT LAMP

Penetrates more compare to non luminous

More efficient tissue heating

Therapeutic effect is mostly due to heating

NON LUMINOUS LAMP

Does not penetrate more deeply

Mostly absorbed in skin

Therapeutic effect is mostly due to sensory heating

DANGERSBURNSRisk of burns can be reduced by:

Testing patient’s ability to differentiate heat levels

Ensure sufficient distance of lamp from the skin

Adequate warning to patient

Checking effect of skin during treatment PT can feel skin or place hand under lamp

Metals should be removed

REDUCE OR ALTER PERIPHERAL BLOOD FLOW

Increased local flow during heating during heating must be sufficient enough to dissipate heat

Arterial disease atherosclerosis, arterial injury or skin grafting is not treated with IR

After IR radiation, & following radiotherapy pt should not be treated with IR

INFECTIONDo not apply heat over local infection

TUMORWith heating tumor cell grow more

SKIN INFLAMMATORY CONDITIONSkin condition become more worst after applying IR

EYE DAMAGE

Prolonged & extensive exposure to IR leads to Cataracts

E.g. in workers of glass factory or furnace men

CONTRAINDICATION

Defective cutaneous circulationAcute skin diseaseImpaired sensationAnalgesic & narcotic drug (it raises pain threshold)Blood pressure abnormalitySevere cardiac conditionFollowing radiotherapySuperficial infectionsTumorMetal in treatment area

TECHNIQUE OF APPLICATION OF IR

PatientApparatusSetting upInstruction & warningapplication

PATIENTPosition: suitable, well supported

Expose area to be treated

Explanation: explain nature & effect of treatment to pt

Examination & testing: examine skin to be treated , rule out for contraindication,& test thermal sensation

APPARATUS

If non luminous lamp is chosen , switch it for at least 5 min before treatment to allow time for it to warm up & reach its maximum emission

Luminous lamp does not require any warm up

SETTING UP

Expose skinCover eyePlace lamp in such a way that radiation strikes at right angleSet a lamp at appropriate distance 60-75 cm for large 750 or 1000 w45-50 cm for smaller ones

INSTRUCTION & WARNINGS

Heat should be of require level

It must not be hot to make burn

Pt should not touch any part of lamp

APPLICATION

Intensity of most IR lamp is controlled by distance of lamp from skinInverse square lawDoubling the distance reduces intensity by one quarterTripling distance reduces intensity to one ninth part

Adjacent area can be protected from heating by placing towel.

Therapist should check level of heating on completion of set up & again after 5-8 min

If require reduce intensity of lamp by increasing distance of lamp from skin

DURATION OF TREATMENT10-15 min

REMEMBER THAT IR IS A PART OF TREATMENT NOT TREATMENT ITSELF

THANK YOU