1. SURGICAL DIATHERMY

2. DIATHERMY: Used during cutting and coagulation of the tissues
Consists of high frequency power oscillators
Spark gap oscillators
Undamped current: clean cutting
Damped current: coagulation

3. Electro surgical unit:

4. Requirement: High temperature exceeding 1000 degree C
1 mm diameter of cross section of arc
High current density
Frequency : 250 Hz to 1 MHz
Cutting : 400 W
Coagulation : 150 W (10-15 s & 15 KHz)

5. Block diagram:
Control panel & logic board: produces the basic signal and timing informations
Operates the relays, give visual indications and determine the alarm conditions
Isolated and carefully insulated
Avoid contact to conducting surfaces.

6. Automated electro-surgical systems:
Size and shape of cutting electrode
Type and speed of cut
Tissue properties
Voltage control or spark control
Programmed processors decides the spark intensity

7. Contd.
Soft coagulation: no electric arcs, prevents skin from carbonized
Forced coagulation: arcs are intentionally generated between the coagulation electrode and the tissue (deeper coagulation)
Spray coagulation: arcs are deliberately produced. Contact is not necessary

8. Electro surgery techniques:
Mono polar technique: depends on the contact area
Bi polar technique : two electrodes. Contact area is less. Safer and precise.

9. Electrodes used: Needle electrode: desiccation
lancet electrode: cutting
Loop electrode : ecsecting (opening) the channels, extirpating growth
Performance: improper placement of electrode
Loss of energy ( Mono phasic electrode)

10. LASER Physiotherapy and electrotherapy equipments
Heat radiation by the application of high frequency radiation (through heating)
Muscles, bones, internal organs etc.
Polarity of the electric field alters, continuous re-alignment of the molecules
Microwaves and ultrasonic waves are used for heating purpose

11. Short wave diathermy:
Hot towels, infrared lamps, electric heating pads
Heat is produced within the body rather not transferred through the skin (to avoid discomfort and skin burns)
Can be controlled precisely
AC frequency : MHz ( no muscle contraction)

12. Circuit diathermy and automatic tuning:
Page no: 762
Anode voltage: 4000 V
Controlling the anode voltage, filament heating current
Adjusting the grid leak resistance, R1.

13. Application technique:
Capacitor plate method:
Tissues are kept sandwiched between the two pads
No direct contact
Also called as Condenser method

14. Contd. Inductive method: The cable is coiled around the arm
RF current is passed and the magnetic field applies the heat (electro static action)
Also called as inductohermy

15. Diapulse therapy: Increase in energy output avoids the dangers of heat
Pulse width : 65 micro second
Interval : 1600 micro second

16. Micro wave diathermy: Frequency : 300 to 30,000 MHz (2450 MHz)
Wavelength : 10 mm to 1 m (12.25 cm)

17. Contd.
Delay circuit
Magnetron circuit
Safety circuit

18. Ultrasonic therapy unit:
Absorption property of the tissues
Piezo electric effect

19. Contd. Controlling the firing angle Frequency of ultrasound
Intensity of ultrasound
Duration of exposure
Avoids injury

20. Apparatus:
Galvanic current:
Steady flow of current
10-20 minutes

21. Contd.
Exponentially progressive current:
Independent pulse duration

22. Contd. Faradic current: Sequence of pulses
With defined shape and current
80 mA of magnitude
25 surges per minute

23. Functional diagram:

24. Contd. Distortion free Irrespective of patient’s resistance
Position of the electrodes should be rigid
Mono-polar electrode : indifferent electrode is placed near to the active electrode.

25. Transcutaneous electrical nerve stimulator:
Gate control theory: prevents pain carrying messages
Endorsphin release theory: stimulation of pain killing substance (Endorsphin)

26. Spinal cord stimulator:
Not for patients using triggered or inhibited type of pacemakers

27. Magnetic stimulator: Electrical stimulator is very painful
Magnetic pulse is generated by passing a brief, high-current pulse through a coil of wire
Still experimental

28. Diaphragm pacing by radio frequency for the treatment of chronic ventilatory insufficency:
Only one phrenic nerve could affect normal oxygen and carbon-di-oxide exchange

29. Contd. Bladder stimulators: Reflex actions can be controlled
Possible kidney malfunction
Cerebellar stimulators:
Inhibiting intractable epilepsy