Chapter 7: Therapeutic Ultrasound
This is the depth where 50% of the ultrasonic energy has been absorbed by the tissues.
Half-Layer Value
Aside from direct coupling, what are other coupling methods?
Bladder/Pad Method and Immersion
This type of diathermy utilizes two plates that places the patient's tissues within the EMF circuit.
Capacitive SWD
What are 3 contraindications for SWD?
Pacemakers/implanted electronics
Metal implants/jewelry
Plastic implants/bone cement (thermal)
Ischemic areas
Acute injury (thermal)
Peripheral vascular disease
Pregnancy
Cancer
Fever
Tendency to hemorrhage
Epiphyseal plates
Genitals
Carotid sinus/eyes/face
If applying ultrasound with a metered output of 2W and a BNR of 6:1, what is the highest intensity value of the beam?
12W
What are the two frequencies used in Therapeutic Ultrasound and what tissue depths do they penetrate?
1 MHz: 5cm
3.3 MHz: 2-3cm
When performing an ultrasound, what are two things that may reduce the effectiveness of your treatment?
air bubbles, hair, too much pressure, too fast
What was the example in class for the volume of tissue SWD can effectively heat?
Size of a cereal bowl
40 feet
To decrease muscle spasm, what tissue temperature increase must be obtained?
3.6-5.4*F or 2-3*C (Moderate)
To achieve a therapeutic effect, how long must the tissues remain elevated?
3-5 minutes
At what speed should the ultrasound head be moved across the skin for the treatment to be effective?
4cm per second
What tissues are selectively heated by induction and capacitive SWD?
Induction: muscles and vessels
Capacitive: skin, adipose, bone
What are the indications that use moderate warmth SWD?
Pain syndromes, muscle spasm, chronic inflammation, increase blood flow
Explain an eddy by drawing a picture
Answer
This is the parameter that measures the intensity during the ON time of a pulse
Spatial Average Temporal Peak
What parameters for continuous and pulsed non thermal ultrasound have been established by the book/evidence?
Continuous: 100% DC at 0.3 W/cm2
Pulsed: 20-25% DC at 0.5 W/cm2
Thermal effects of SWD are obtained when the total amount of energy delivered to the patient's body is greater than ______ W. (Thermal effects can happen with pulsed SWD)
38
How far should all metal (jewelry, zippers, phones, etc) be from the patient when delivering continuous and pulsed SWD?
Continuous: 3 ft
Pulsed: 1.5 ft
How does phonophoresis assist with the absorption of medications into tissues?
Opens pores, increases cellular permeability/bloodflow
By how many degrees can tissue temperatures increase per minute using 3 MHz ultrasound?
1.1*F or 0.6*C
Split into treatment zones.
How does tissue density affect the amount of heat generated in it?
Increased Eddy Currents = More Friction = More Heat
What is the parameter that adjusts the output resonance to match the patient's tissues?
Tuning
During shortwave diathermy, high frequency electromagnetic energy is changed to heat by the process of what?
Conversion