INTRODUCTION, SOURCES OF IRR, TYPES OF IRR, PRODUCTION OF IRR, NON LUMINOUS LAMP, LUMINOUS LAMP, ABSORPTION & PENETRATION, PHYSIOLOGICAL EFFECTS, THERAPEUTIC EFFECTS, CHOICE OF LAMPS, DANGERS, CONTRAINDICATIONS,

1. INFRA
RED
RADIATION
DR NIYATI PATEL
MPT IN NEUROLOGICAL CONDITIONS

2.  Infrared radiations are part of an electromagnetic spectrum,
with wavelength of 750nm-1mm, and frequency of 4x1014
and 7.4x 1011, and located between microwave and visible
light.
 Infrared is superficial Heating modality (penetration depth 1-
10mm).
 Infrared is radiant heat transmits energy by radiation.

3. Sources of IR
Artificial
Luminous
Non-
luminous
Natural Sun 60%
Near IRR
Far IRR

4. TYPE WAVELENGTH
IR A 750 – 1400 nm
IR B 1400 – 3000 nm
IR C 3000 nm – 1mm (not used in
therapy)
FORMER
CLASSIFICATION
Near or short IR 750 – 1500 nm
Far or long IR 1500 – 15000 nm

5. Near (short)=
750-1500nm
Far (long)=
1500-15000nm
Types IRA=750-1400nm IRB=1500-3000,
IRC=3000nm-1m
Source Luminous heated body
-Incandescent bodies
-Sun
-Tungsten
Non-luminous Heated bodies
-Hot pack
-Electrical heating pads
Penetration Deeper;
penetrates to epidermis , dermis
& subcutaneous (5-10mm)
Superficial;
penetrates to the epidermis
≤5mm
Absorption Deep Superficial

6. IR radiation :
 Emitted from any heated body.
 Divided into long & short wavelength for
therapeutic purposes.
 Produce heat when absorbed.

7.  Any heated material will produce IR radiation, the
wavelength being determined by the temperature.
 If short IR is to be produced efficiently , the material must
not be oxidized (burnt) by the higher temperature used.
 Most convenient method is to heat a resistance wire by
passing an electric current through it.
 An ordinary household electric fire can be made of a coil of
suitable resistance wire, such as nickel – chrome alloy, wind
on a ceramic insulator.

8. Infrared lamps are used for therapy
Non luminous generators Luminous generators
1. Non luminous generators
 Ceramic material when heated to a lower temperature than
the wire, gives only IR & no visible radiation. Therefore
therapy lamps have wire embedded in the insulating
ceramic (or porcelain or fireclay).
 The heater wire can also be mounted behind a metal plate
or inside a metal tube which does not become red- hot but
emits IR.
 All parts of the lamp becomes hotter – the emitter, the metal
plate on the end of the emitter, the protective wire mesh and
the reflector – giving IR.

9.  Emitter is placed at the focus of a
hemispherical or parabolic reflector to
reflect the radiations into an approx
uniform beam.
 When such lamps are switched on, they
require some time to warm up b’coz of the
thermal inertia of the considerable mass of
the metal & insulating material that has to
be heated; thus small lamps take abt 5mins
but larger one takes 15mins to reach max.
emission ( Forster & Palastanga, 1985).

10. 2. Luminous generators
 also k/a incandescent lamps.
 Consist of tungsten filament in a large glass
envelope which contains inert gas at low
pressure.
 Part of Inside of glass bulb is silvered to
provide reflector.
 Current pass  filament heated 
continuous spectrum of IR & visible
radiations.
 No oxidation  coz no O2 only trace of
inert gases.
 Radiation from long infrared upto UV are
absorbed by glass & therefore not
transmitted by lamp (Ward, 1986).

11. Non-Luminous Luminous
Sources &types Electrically heated
resistance wire coiled. It
takes about 5-15 minutes to
be heated and emit their
maximum intensity, e.g.
Hot pack
Electrically heated filament
e.g. Quartz lamp, Tungsten
lamp, Carbon filament
lamp
wavelength 1500-12000nm (maximum
4000nm)
350-4000nm (maximum
1000nm)
Emission 90 % far IRR, and 10%
near IRR.
70% near IRR, 24% far
IRR,
5% visible light, & 1% UV
Penetration Epidermis & superficial
dermis (2mm)
Epidermis, dermis &
subcutaneous tissue (5-
10mm)
Uses Acute conditions. Chronic inflammation
Physiological effect Pain reduction via sedative
effect
Pain reduction via counter-
irritant effect
Treatment time 20-30minutes 15-20minutes

12.  Infra red rays are electromagnetic waves with wavelength of
750 nm – 1mm.
 There are 2 main two groups the NON – LUMINOUS &
LUMINOUS generators.
 NON – LUMINOUS = Infra red rays only.
 LUMINOUS = Infrared rays + visible and few UV rays.
 RADIANT HEAT = Treatment with luminous generators.
 INFRA RED = Radiation from non – luminous sources.

13.  Smaller lamps (luminous & non luminous) = 250 – 500 W.
 Larger non luminous = 750 – 1000 W.
 Larger luminous = 600 – 1500 W.

14. Non – Luminous
 3000 – 4000 nm (long IR) , 10% between 1500 nm & visible
(short IR)
Luminous
 Approx 70% short IR.
 5% visible.
 24% long IR.
 1% UVR absorbed by glass of bulb.
(Wadsworth & Chanmugan, 1980)

15. reflected
Radiation striking penetrated
on surface of skin scattered
refracted
absorbed

16.  95% absorption takes place when radiation applied
perpendicular (Ward, 1986).
 Water & Proteins are strong absorbers of IR.
 Therefore any radiation entering the skin depends upon ---
1. Structure
2. Vascularity
3. Pigmentation of the skin
4. Wavelength of the radiation

17.  Usual method is to give penetration depth.
 Penetration depth = It is the depth at which approx. 63% of
the radiation energy has been absorbed & 37% remains.

18. 1. Cutaneous vasodilation
Heating with IR
Local cutaneous vasodilation
After a short latent period of 1-2 min (Crockford & Hellon, 1959)
Direct effect on blood vessels
thru polymodal nociceptors by
axon reflex mechanism
Liberation of chemical
Vasodilators like histamine &
other substances

19. 2. Sweating
Prolonged heating
Sweating
absorb the applied IR radiation
surface cooling as it evaporates
allow better penetration

20. 3. Sensation
 Thermal heat receptors stimulated in the skin so patient is
aware of the heat.
4. Increase in metabolism
Increase in temperature
Increase in metabolism.

21. 5. Chronic changes
Excessive & prolonged IR application
Destruction of erythrocytes
Releasing pigments
Brown discoloration

22. 1. Reduction in muscle spasm
2. Acceleration of healing & repair
3. Fungal infection which are difficult to control & thrive in
moist condition e.g. paronychia.
4. Treatment of psoriasis also pressure sores
5. For pain relief
Increase in sensory nerve conduction might influence
sensory responses via increase in endorphins, which could
affect the pain gate mechanism ( Kitchen & Partridge, 1991)

23.  Luminous = efficient for tissue heating since it penetrates
further (bcoz peak emission is in short IR) & therefore the
energy is distributed in a larger volume of tissue.
 Non – Luminous = peak emission around 4000nm, absorbed
almost entirely in the skin
As the total heating is limited by the sensation felt by
the patient, & thermal sense organs are close to the skin
surface, it is evident that the non – luminous radiation will
reach the limit of tolerable heating with a lower intensity
than the luminous.

24. If the desired effects are due to :
 Heating = Luminous shorter IR source is preferred.
 Sensory stimulation = Non – Luminous

25. 1. BURNS
Occurs if the patient
 Unaware of heat coz of defective sensation or reduced
consciousness.
 Mentally abnormal or masochistic patient may stoically
tolerate painful & damaging levels of heat.
 Accidental touching the hot elements if there is no
protective guard
Avoided by :
 Careful application
 Adequate warnings to patient
 Checking the effect of heat during the application

26. 2. SKIN IRRITATION
 Acute inflammatory condition
 Chemical irritants on the skin
3. AREAS OF DEFECTIVE ARTERIAL BLOOD FLOW
 Areas affected by arterial disease such as atherosclerosis,
arterial injury or after skin grafting.
 This can result to tissue necrosis (gangrene) of such affected
tissues.

27. 4. LOWERED BLOOD PRESSURE
IR
Cutaneous vasodilation
Temporary lowering BP esp. in elderly patient having less
vasomotor control
Faintness on getting up immediately after T/t can also cause
headache.

28. 5. EYE DAMAGE
 Long term irradiation, corneal burns = far IR
Retinal & lenticular damage = near IR
( Moss et.al , 1989)
 IR applied to the eyes causes the dryness & thus dehydration.
6. DEHYDRATION
 Prolonged & intensive T/t to large parts cause sweating &
provoke dehydration if water is not replaced

29. 1. Defective cutaneous circulation.
2. Acute skin disease, e.g., dermatitis or eczema.
3. Following radiotherapy
4. Superficial infections or tumors.

30. 1. INCREASES THE EXTENSIBILITY OF COLLAGEN TISSUES
 Tissues heated to 45°C and then stretched exhibit a non-
elastic residual elongation of about 0.5 – 0.9% that persists
after the stretch is removed which does not occur in these
same tissues when stretched at normal tissue temperatures.
 Thus 20 stretching sessions can produce a 10 – 18%
increase in length in tissues heated and stretched.
 This effect would be especially valuable in working with
ligaments, joint capsules, tendons, fasciae, and synovium
that have become scarred, thickened or contracted.

31. › Such stretching at 45°C caused much less weakening in
stretched tissues for a given elongation than a similar
elongation produces at normal tissue temperatures.
› The experiments cited clearly showed that low-force
stretching can produce significant residual elongation when
heat is applied together with stretching or range-of-motion
exercises, which is also safer than stretching tissues at
normal tissue temperatures.
› This safer stretching effect is crucial in properly training
competitive athletes so as to minimize their "down" time
from injuries.

32. 2. DECREASES JOINT STIFFNESS
› There was a 20% decrease in stiffness at 45°C as
compared with 33°C in rheumatoid finger joints, which
correlated perfectly to both subjective and objective
observation of stiffness.
› Any stiffened joint and thickened connective tissues
should respond in a similar fashion.

33. 3. RELIEVES MUSCLE SPASMS
› Muscle spasms have long been observed to be reduced
through the use of heat, be they secondary to underlying
skeletal, joint, or neuropathological conditions.
› This result is possibly produced by the combined effect of
heat on both primary and secondary afferents from
spindle cells and from its effects on Golgi tendon organs.
› The effects produced by each of these mechanisms
demonstrated their peak effect within the therapeutic
temperature range obtainable with radiant heat.

34. 4. PRODUCES PAIN RELIEF
› Pain may be relieved via the reduction of attendant or
secondary muscle spasms.
› Pain is also at times related to ischemia due to tension or
spasm which can be improved by the hyperemia that
heat-induced vasodilation produces, thus breaking the
feedback loop, in which the ischemia leads to further
spasm and then more pain.

35. › Heat has been shown to reduce pain sensation by direct
action on both free-nerve endings in tissues and on
peripheral nerves.
› In one dental study, repeated heat applications led finally
to abolishment of the whole nerve response responsible
for pain arising from dental pulp.
› Heat may both lead to increased endorphin production
and a shutting down of the so-called "spinal gate" of
Melzack and Wall, each of which can reduce pain.

36. 5. INCREASES BLOOD FLOW
› Heating of one area of the body produces reflex-
modulated vasodilations in distant-body area, even in the
absence of a change in core body temperature; ie. heat
one extremity and the contralateral extremity also dilates:
heat a forearm and both lower extremities dilate; heat the
front of the trunk and the hand dilates.
› Heating of muscles produces an increased blood flow
level similar to that seen during exercise.

37. › Temperature elevation produces an increase in blood flow
and dilation directly in capillaries, arterioles and venuies,
probably through direct action on the smooth muscles. The
release of bradykinin, released as a consequence of sweat-
gland activity, also produces increased blood flow and
vasodilation.
› Whole-body hyperthermia, with a consequent core
temperature elevation, further induces vasodilation via a
hypothalamic-induced decrease in sympathetic tone on the
arteriovenous anastomoses.
› Vasodilation is also produced by axonal reflexes and by
flexes that change vasomotor balance.

38. 6. ASSIST IN RESOLUTION OF INFLAMMATORY INFILTRATES,
EDEMA & EXUDATES
› The increased peripheral circulation provides the
transport needed to help evacuate edema which can help
end inflammation, decrease pain and help speed healing.

39. 7. MOST RECENTLY, CANCER THERAPY
› This is a new and experimental procedure.
› It shows great promise in some cases when used properly.
› American researchers favor careful monitoring of the
tumor temperature; whereas, the successes reported in
Japan make no mention of such precaution.

40. 8. AFFECTS SOFT TISSUE INJURY
 Infrared healing is now becoming a leading edge care for
soft tissue injuries to promote both relief in chronic or
intractable "permanent" cases, and accelerated healing in
newer injuries.