Microwave diathermy uses electromagnetic radiation between shortwave diathermy and infrared to generate heat in superficial tissues. It works by producing an electric field that heats tissues. The document discusses how microwaves are produced using a magnetron and antenna, their physiological effects from heating tissues, absorption patterns in different tissues, and therapeutic uses for deep heating. Safety considerations are also outlined.
3. INTRODUCTION
Microwave diathermy between short wave diathermy and infrared radiation
Penetration not deep as SWD
Generate strong electric field with weak magnetic field
Higher frequency and smaller wavelength than SWD
1 m to 1 mm 300 MHz to 300 GHz
Frequency (MHz) Wavelength (cm)
2450 12.2
915 32.8
434 69.1
4. PRODUCTION OF MICROWAVES
Antenna a wire which produce EMR
Magnetron generates higher power level alternating current to antenna as well
as different frequency ; different magnetron
A wire attached with metal reflector
A delay switch to allow time for the magnetron to reach its proper working
temperature
A standby switch without switching off magnetron treatment can be varied.
Continuous or pulsed mode
7. THE PATTERN OF MICROWAVE
ABSORPTION IN THE TISSUE
Absorption penetration depth is small
At 2450 MHz, reflection with skin and fat thickness from 50-75%
Due to reflection, more superficial heating than expected.
10. HEATING EFFECT
15 minutes MWD will prolong heating in to deep muscles upto more 20
minutes
the theoritical absorptionpattern indicates absorption in the skin, fat,
muscle
the widely used 2450 MHz has a less satisfatory absorption pattern for
therapeutic purpose than lower frequencies
the shape and size of the emitter influences the energy distribution on to
the tissue
higher transmission - contact emitter
few cm in tissue heating
2450 MHz increses blood flow more.
12. METHODS OF APPLICATION
STAGES :
1. Patient explanation and examination
2. Apparatus
3. Preparation of part
4. Setting up
5. Instructions and warnings
6. Application
7. Termination
13. DOSAGE
Intensity 200 mW/cm2
SAR specific absorption rate W/Kg
50-170 W/Kg
Duration 15- 20 min minimum
14. POTENTIAL DANGERS
Effects of metal
Effects of changed blood flow
Effects of surface moisture
Implanted electronic equipment
The eyes
The testes
Pregnancy
Other local pathologies