Lecture #8 (Diathermy)

Question 1

What is diathermy?

Answer 1

The application of high frequency electrical energy that is used to generate heat in body tissues as a result of the resistance of the tissue to the passage of energy.

Question 2

Is diathermy typically a superficial or deep modality? Why?

Answer 2

Superficial because of its short wavelength.

Question 3

True or false:

Diathermies do not crease muscle or nerve depolarization?

Answer 3

True because of their short wavelengths.

Question 4

What is an important effect of the heating effects of diathermy?

Answer 4

Increases blood flow.

Question 5

What can 1 degree C do? 2-3 degrees? 3-4 degrees?

Answer 5

1 degree= reduce mild inflammation and increase metabolism
2-3 degrees= decrease pain and muscle spasm
3-4 degrees cause tissue extensibility (this is optimal)

Question 6

True or false:

The deep heat from diathermy tends to cause greater effects with pathological conditions than other forms of heat.

Answer 6

True, it seems to stay in the body longer (30 minutes) than other heat producing agents such as ultrasound (10 minutes)

Question 7

What are four benefitsof diathermy?

Answer 7

• Capable of heating larger area than ultrasound
• Hands-free treatment
• Provides deeper heat than moist hot packs
• Heat stays in the tissue longer

Question 8

What determines the amount of energy absorbed per unit of area of tissue mass?

Answer 8

SAR (specific absorption rate)

Question 9

What are the four doses of heat and what do they mean?

Answer 9

Dose I (lowest)= no sensation of heat
Dose II (low)= mild heating sensation
Dose III (medium)= moderate heating sensation; comfortable heating
Dose IV (heavy)= vigorous heating that is tolerable below the pain threshold.

Question 10

True or false:

Diathermy creates only an electric field.

Answer 10

False: diathermy creates both an electric and magnetic field (electric= short wave lengths, and magnetic= long wave lengths).

Question 11

What frequency of shortwave units produces a stronger magnetic field?

Answer 11

13.56 Hz.

Question 12

What frequency of shortwave units produces a stronger electric field?

Answer 12

27.12 Hz.

Question 13

What type of tissue will the greatest amount of heat be in?

Answer 13

One that creates the greatest resistance to the current flow.

Question 14

What are capacitor electrode?

Answer 14

Air space plates or pads that create a stronger electrical field than magnetic field. The ions move from positive to negative polarities and the patient becomes part of the electrical circuit.

Question 15

What type of electrodes have the cable, coil, or drum type of electrode and the patient is not a part of the electrical circuit?

Answer 15

Induction electrodes

Question 16

True or false:

Pulsed shortwave diathermy is used primarily for its non-thermal effects.

Answer 16

True

Question 17

What are the electrodes called when working with microwave units?

Answer 17

Applicators.

Question 18

Why must the surface be flat when working with microwave diathermy?

Answer 18

Otherwise the beam will be easily reflected. Therefore the applicators should be aimed perpendicular to tissue.

Question 19

Which diathermy creates stronger electrical fields?

Answer 19

Microwave.

Question 20

Which diathermy creates stronger magnetic fields?

Answer 20

Shortwave.

Question 21

Which diathermy has a greater depth of penetration?

Answer 21

Shortwave because it can penetrate the fat layer of the body.

Question 22

What are indications of diathermy?

Answer 22

Post acute injuries, increased blood flow, vasodialation, increased metabolism, increased enzyme activity, increased collagen extensibility, muscle relaxation, increased pain threshold, absorption of hematoma, increased nerve growth and regeneration, enhanced injury recovery, and heat up a larger area.

Question 23

What are the contraindications of diathermy?

Answer 23

Acute injuries, inflammatory conditions, ischemic areas, reduced sensation, fluid filled areas (joint effusion), head and face, malignancies, infection, near reproductive organs, growth plates, and metal (implants, jewerly)