Infrared Radiationnn

INFRARED RADIATION

 

Electromagnetic spectrum

                                               

 

                                                       

 The

spectrum contains all kinds of radiation which are distributed by their different wavelength



Electromagnetic radiation: all types of radiation from the X-rays used at hospitals, to radio waves used for communication, and even the microwaves you cook food with.

Radio wave

0.1mm – 100 km 750nm – 0.4 mm 400nm – 750 nm 10nm – 400 nm 0.01pm – 100 nm

Infrared wave Visible light Ultraviolet X-ray Gamma rays 100nm Cosmic

Gamma

400nm

Ultra-violet

X-ray 10nm

Visible

750nm Infra-red

radio 5 10nm

 wavelength

of an electromagnetic wave is the distance between wave crests.

 Frequency.

The no. of complete wave passing any fixed point in one sec.  A single unit of frequency is equal to one cycle per second.  Long

waves- low freq  Short waves – high freq

 Velocity

waves

is constant for all electromagnetic

Short wavelength radiation is of the highest energy and can be very dangerous - Gamma, Xrays and ultraviolet are examples of short wavelength radiation.  Longer wavelength radiation is of lower energy and is usually less harmful - examples include radio, microwaves and infrared. 

 Visible

and infrared radiation are used therapeutically  Characterized by wavelengths of 760nm – 1mm  Many sources which emit visible light or ultraviolet radiation also emit IR

Infrared and visible radiations Type IRA IRB IRC

Wavelength 760-1400 nm 1400-3000 nm 3000nm –1mm

Former classification Near or short IRR Far or Long IRR

760-1500 nm 1500-15000nm

IRR  Is

emitted from any heated body.  Are divided also into long and short wavelengths for therapeutic purposes  Produces heat when absorbed  Visible radiations produce chemical changes as well as heat when absorbed.

Production of Infrared  Any

heated material produces IRR  Wavelength is also determined by temperatures  For production of short infra red the material should not be oxidised

Generator      

Non-luminous generator – similar to electric heater Coil of Wires wound on a cylinder of some insulating material such as fireclay or porcelain Electric current is passed through wire and produce heat IR is emitted from hot wire and from fireclay which is heated by conduction Radiations are visible Ceramic is heated to lower temp than the wire gives mainly IR &little visible radiation

 In

therapeutic use the wire is embeded in insulating ceramic so little or no visible radiation is emitter  Produce long IRR around 3000 or 4000  Small have power of 250-500W  Larger have power of 750- 1000W

Luminous  Electrically

heated filament in an evacuated glass bulb,oftenwith silver inner surface to provide a reflector  Both IRR & visible radiation  Small have power of 250-500W  Larger have power of 600- 1500W

Generators Two types  Luminous and non-luminous generators  Power output   



Smaller lamps (both types) 250-500W Large, non luminous 750-1000W Large Luminous , 600-1500 W

Emission     

Non-luminous 3000-4000 mainly and 10% between 1500nm and visible Luminous approximately 70% short IR 5% visible 24% long IR 1% UVR absorbed by glass of Lamp.

Absorption and penetration  The

result of any kind of radiation applied to the skin depends on    

Structure Vascularity Pigmentation of the skin Wavelength of the radiation

Penetration  

 

 

Penetration depth Very long infra red like MWD –penetrates several cm. Long infra-red only at surface 3000nm=0.1mm From here increasing penetration with decreasing wavelength At 1000nm penetration depth 3mm Again very short and red –lesser penetration to 12mm

Penetration and absorption 

 





Since penetration only few mm hence will not be absorbed directly by deeper tissues Hence superficial heating only max up to dermis For deeper heating through conduction of heat and increased local circulation Infra red radiation is strongly absorbed near the skin area Most effective penetration is band between 6501500nm or IRA

Physiological effects and therapeutic uses  



 

Physiological increases metabolic rate cutaneous vasodilatation sweating stimulation of sensory nerve

   

Therapeutic pain relief reduces muscle spasm acceleration of healing and repair

Application  Preparation

of apparatus  Preparation of patient  Examination and testing  Setting up- rt angle ,dist -60-75cm,45-50cmsmall lamp  Instructions and warnings  Application  Termination of treatment

Dangers with treatment  Burns  Skin

Irritation  Lowered blood pressure  Areas of defective arterial blood flow  Eye damage  Dehydration

Contraindications        

Impaired cutanoeus thermal sensation Defective arterial cutanoeus circulation Patients whose consciousness is lowered Acute skin disease Skin damage due to x-ray therapy or other radiation Defective blood pressure regulation Acute febrile illness Tumors of skin