1. Shortwave and Microwave Diathermy
Jennifer Doherty-Restrepo, MS, LAT, ATC
Entry-Level ATEP
Therapeutic Modalities

2. Diathermy Application of high-frequency ___________________ energy
Used to generate ______ in body tissues
______ produced as a result of the __________ of tissues to the passage of energy
___________ diathermy
Used for ________________ effects
Renewed interest due to research documenting efficacy

3. Physiologic Responses To Diathermy: Thermal Effects
Tissue temperature __________
Increased blood flow (vasodilation)
___________ venous and lymphatic drainage
___________ metabolism
Changes in physical properties of tissues
Muscle _________
Analgesia

4. Diathermy Heating
Diathermy parameters are not precisely controlled, thus the amount of heating cannot be accurately measured
Heating occurs in proportion to the square of the current density and in direct proportion to the resistance of the tissue
Heating = ______ X ________

5. Physiologic Responses To Diathermy: Non-Thermal Effects
Pulsed shortwave diathermy is used to treat ________ injuries and wounds
Mechanism of effectiveness is related to the _____________ of damaged cells
Loss of cell division
Loss of proliferation
Loss of regenerative capabilities
____________ occurs with treatment, thus correcting cell dysfunction
Not capable of producing _____________ to elicit muscle ______
Wavelengths too short

6. Shortwave Diathermy Shortwave diathermy unit is a radio transmitter
Three frequencies available:
______ MHz, wavelength of 11 m
______ MHz, wavelength of 22 m
______ MHz, wavelength of 7.5 m

7. Shortwave Diathermy Unit
_______________: provides power to radio frequency oscillator (RFO)
____: provides stable, drift-free oscillations at given frequency
_____________: generates power to drive electrodes
__________________:tunes in the athlete as part of the circuit to allow for maximum power transfer

8. Shortwave Diathermy Unit
A =Power switch
B = Timer
C = Power meter
Monitors current from power supply, not current entering patient
D = Output intensity (% max power to patient)
E = Tuning control (tunes output from RFO)

9. Shortwave Diathermy Unit
Power output should provide energy to ______ tissue temperature to therapeutic range
Therapeutic range = ___________
____________________________: represents the rate of energy absorbed per unit area of tissue mass
Power range required to elicit tissue temperature increase = ____________

10. Adjusting the Shortwave Diathermy Unit
________________: adjusts patient circuit
Set output intensity at ______ of maximum
Adjust tuning control until power output meter reaches ______
Then adjust down to ______________, which is about 50% of maximum output
If patient is able to tolerate more than 50% of maximum output, he/she is ___________________
________________: automatically sets output intensity
Automatically turns off if patient is _______________

11. Shortwave Diathermy Unit
Generates both an _______ and a _______ field
Ratio depends on characteristics of both the ______ and the _________
SWD units at MHz = stronger ________ field
SWD units at MHz = stronger ________ field

12. SWD Electrodes 2 types of electrodes
_____________________
Air space plates
Pad electrodes
Cable electrodes
Drum electrodes
Selection of appropriate electrodes can influence the treatment

13. Capacitor Electrodes Create stronger ______ field than ______ field
Ions will be attracted or repelled depending on the charge of the ______

14. Capacitor Electrodes Electrical field
Lines of force exerted on charged ions that cause _____________________ ________________r
______ has higher current density than __________

15. Capacitor Electrodes Patient is between electrodes
Becomes part of circuit
Tissue is between electrodes
__________ circuit arrangement

16. Electrical Field
The tissue that offers the greatest resistance to current flow develops the __________
Fat tissue ______ current flow
Therefore, tissues with a ______ fat content are heated in an electrical field
Typical with capacitor-type electrodes

17. Capacitor Electrodes: Air Space Plates
Two metal plates surrounded by glass or plastic guard
Metal plates can be adjusted 3cm within guard
Produce ________________ oscillating current
When one metal plate is overloaded, it discharges to other plate of lower potential

18. Capacitor Electrodes: Air Space Plates
Area to be treated is placed between electrodes
Treatment area becomes part of the external circuit

19. Capacitor Electrodes: Air Space Plates
Sensation of heat in _____ proportion to the distance of metal plate from the skin
The closer the plate to the skin, the _____ the energy transmission (______ reflection)
Generates more surface heat in ____ and _____________

20. Capacitor Electrodes: Pad Electrodes
Greater ______ field than ______ field
Patient is between electrodes
Becomes part of external circuit

21. Capacitor Electrodes: Pad Electrodes
Must have uniform contact pressure on the body
Toweling to prevent burns
Spacing between electrodes is equal to the ____________ ________ of pads

22. Capacitor Electrodes: Pad Electrodes
Area to be treated should be ______ between electrodes
Increasing the space between electrodes will ______ the depth of penetration but will _________ the current density
Vice versa also true

23. Induction Electrodes
Creates a stronger ________ field than ________ field
A cable or coil is wrapped circumferentially around an extremity or coiled within an electrode
Passing electrical current through coiled cable creates a ________ field by inducing ________ _________
Small circular electrical fields that generate heat

24. Induction Electrodes Patient placed in a magnetic field
NOT part of a circuit
Tissues in treatment area are in _________ arrangement to magnetic field
Greatest current flow through tissue with least resistance
Tissue high in __________________ respond best to a magnetic field

25. Induction Electrodes: Cable Electrode
Two arrangements:
Pancake coils
Wraparound coils
Requires at least ____ of toweling between skin and coil
Spacing between turns in coil must be ______

26. Induction Electrodes: Drum Electrode
One or more monopolar coils rigidly fixed in a housing unit
May use more than one drum depending on treatment area
Toweling important to prevent ______

27. Continuous Shortwave Diathermy
Patient sensation provides basis for recommendations of continuous SWD
Dose I (______): no sensation of heat
Dose II (______): mild heating sensation
Dose III (______): moderate or pleasant heating sensation
Dose IV (______): vigorous heating with pain threshold

28. Pulsed Shortwave Diathermy
Pulsed electromagnetic energy (PEME)
Pulsed electromagnetic field (PEMF)
Pulsed electromagnetic energy treatment (PEMET)

29. Pulsed Shortwave Diathermy

30. Pulsed Shortwave Diathermy
Interrupted output delivered in series of high-frequency bursts (______)
______ _____selected with pulse frequency control
Off-time ______ than on-time
Mean power output is ______
Uses drum electrode

31. Shortwave Diathermy vs. Ultrasound
Pulsed SWD produces the same magnitude and depth of muscle heating as 1 MHz ultrasound
(Draper, JAT 1997)

32. Shortwave Diathermy: Treatment Time
Typically, minutes
Reminder:
As skin temperature rises, resistance falls

33. Microwave Diathermy Two frequencies available:
2456 MHz
915 MHz
______ frequency and ______ wavelength as compared to shortwave diathermy
Generates strong ______ ______ and relatively little ________ field
Depth of penetration is minimal in areas with subcutaneous fat > 1 cm

34. Microwave Diathermy Unit
A = Power switch
B = Timer
C = Output meter (indicates relative output in Watts)
D = Power output level knob
E = Amber light - warming up; Red light - ready

35. Microwave Diathermy Electrodes
Circular-shaped electrodes
4” or 6” in diameter
Maximum temperature at periphery
Rectangular-shaped electrodes
4.5” x 5” or 5” x 21”
Maximum temperature at center

36. Microwave Diathermy: Electrode Set-Up
915 MHz units
Electrodes are placed 1 cm from skin
2456 MHz units
Manuel includes manufacturer recommended distances and power outputs (uses antenna)
Reminder: Cosine Law
Energy should be administered at ______ to reduce ______

37. When Should Diathermy Be Used?
If the skin or some underlying soft tissue is tender and is unable to tolerate pressure
When The Treatment Goal Is To Increase Tissue Temperatures In A Large Area
In areas where subcutaneous fat is thick and deep heating is required