Electrotherapy (Infrared) Flashcards
What is electrotherapy ?
Electrotherapy is the use of electrical energy as a medical treatment.
Using electricity to reduce pain,improve circulation , repair tissues and strengthen muscles , leading to improvement in physical functioning..
What is thermotherapy?
Also called heat therapy uses physical agents to induce superficial or deep heat to increase soft tissue extensibility, reduce pain , improve circulation , and accelerate healing.
Types of superficial heating modalities
- Hydrocollator pack
- Infrared radiation
- Paraffin wax bath
What is temperature?
The measure of the average amount of kinetic energy possessed by each individual molecule of a body.
Mention (6) Physical effect of heat?
# Expansion # Change of state # acceleration of chemical reaction # production of electromagnetic waves (IR, white lights ) # reduction of viscosity of fluids #Thermionic emission
(8) PHYSIOLOGICAL EFFECT OF HEAT
depends upon several factors
Including :
- Extent of tempt rise
- Rate at which energy is being added to the tissue.
- Volume of tissue exposed
- Composition of the absorbing tissue
- Capacity of the tissue to dissipate heat.
- Thermal conductivity of skin and tissue.
- Size of the tissue exposed
- Duration of tissue tempt elevation or reduction..
Short note on infrared ?
Slightly more than half of the energy from the sun that arrives in earth is in the form of IRR
*IRR are EM waves
Wavelength of 750nm to 400000nm
*It lies between visible lights and microwaves.
* It has higher frequency but lower wavelength than microwave
*It has lower frequency and longer wavelength than visible lights.
Classification of infrared
*Near or short (IRA)
Have a wavelength between 770nm to 1500nm
*Far or Long (IRB)
Have a wavelength between 1500nm to 12000nm
*IRC
Have a wavelength of 3000nm to 1mm (not used in therapy)
WIEN’S LAW
States that the wavelength of maximum production of a radiation is inversely proportional to the absolute temperature of the source.
Types of infrared lamp
- Non luminous generator.
* Luminous generator.
About Non- luminous generator
- also known as low temperature generators
- Produces only infra red rays of wavelength 750nm to 1500nm
#they are usually produced from heated elements of which there are 3 basic types: 1.coil of wire wound round a cylinder of insulating material.
- coil and insulator in an encasement of same insulating material
- U-shaped steel tube enclosing a spiral wire.
About luminous generator
- Also know as high temperature generators
- Emits visible rays , UV rays , and infra red rays of wavelength of 350nm to 4000nm
- Similar to lamps used for House lightening
*Are in form of incandescent bulb Consists of : -A wire filament enclosed in a bulb -May contain inert gas at low pressure. -filament made of tungsten or carbon.
Accessories of Luminous generator
Localizer: facilitate the different sizes
Filter: absorbs visible rays and UV rays..
Variable Resistance: adjusts the output of rays
Production of IRR(4)
- produced as a result of molecular motion within heated material
- Increase in tempt above absolute zero results in the rotation and vibration of molecules within the material.
- The wavelength of the IR is dependent on the temperature of the material
- The higher the temperature the higher the frequency the shorter the wavelength.
Absorption of radiation
depends on: (3) and explain
*The frequency or wavelength:
Wavelength longer than 3000nm is absorbed by the moisture present in the skin.
-Both long and short wavelength are absorbed by moisture present in the skin, thus reducing the absorption of heat.
- 11% of luminous or short IRR is absorbed by the glass of the bulb
33% are reflected by the skin , 56% is absorbed of the rays and 36% is absorbed in the epidermis, 10% goes deeper into the dermis and the remaining is scattered in the epidermis.
The long IRR 36% is reflected, 20% is absorbed in superficial epidermis ,16% reaches the deep epidermis ,
19% penetrate up to dermis , 11 % is absorbed by the glass of the bulb.
- The angle of incidence from the source :
According to Lambert’s cosine law , the angle of incident determines the amount of radiation absorption.
Absorption at 90° of incident is maximum due to zero reflection
For every 15° increase in angle of incidence there is 3% decrease in absorption.
*Distance of the source:
Obeys inverse square law
The intensity of the radiating energy is inversely proportional to the square of the distance between the source and the surface being radiated.