*5.PTA 200-Ultrasound

Question 1

16,000 – 20,000 Hz

Answer 1

Audible sound

Question 2

10 MHz (10,000,000 Hz)

Answer 2

Diagnostic ultrasound

Question 3

1-3 MHz (1,000,000 Hz – 3,000,000 Hz)

Answer 3

Therapeutic Ultrasound

Question 4

Primary mechanism for energy transfer with ultrasound interventions is

Answer 4

CONVERSION

Question 5

the control panel. Plugs into the wall and provides the electrical energy (alternating current) to be converted to sound energy.

Answer 5

Generator

Question 6

inside the transducer of the ultrasound machine: converts electric energy into mechanical energy as sound waves via the reverse piezoelectric effect. Electrical energy causes rarefactions and compressions of the crystal which create the waves.

Answer 6

Crystal

Question 7

transfers the acoustic energy created by the vibrating crystal to the skin and underlying tissues.

Answer 7

Soundhead

Question 8

the “wand” that is held and moved to administer the ultrasound treatment. The “handle” of the machine. Houses the cable, crystal and soundhead.

Answer 8

Applicator

Question 9

Affects the depth of penetration. -Amount of cycles of waves per second. (Hertz)

Answer 9

Frequency

Question 10

*Increased intensity does not increase depth of penetration!!! - amount of energy being delivered per unit of area. (Watts per square centimeter.)

Answer 10

Intensity

Question 11

can penetrate up to 6 cm deep.
*Remember: higher frequencies produce LESS penetration
*helpful memorization tool: “I’m #1!” The winner goes to the frequency that penetrates the most.
(Most effects at 1.25 cm) Energy is absorbed 3 x’s faster, therefore will heat superficial tissue more quickly and penetrate less.

Answer 11

1 MHz

Question 12

can penetrate up to 2.5 cm deep
(Most effects at 1.25 cm) Energy is absorbed 3 x’s faster, therefore will heat superficial tissue more quickly and penetrate less.

Answer 12

3 MHz

Question 13

conversion of the mechanical energy to heat energy; absorption increases with increased frequencies which is why higher frequencies penetrate less

Answer 13

Absorption

Question 14

sound waves are absorbed by the tissues as they pass through and therefore the deeper they travel, the less intense they become. (thus the ½ value layer rule).

Answer 14

Attenuation

Question 15

energy is directed away from the surface at an angle equal and opposite to the initial angle; 100% reflection of US waves in air therefore must use a coupling medium to transfer the waves to the tissue rather than being reflected away.

Answer 15

Reflection

Question 16

when a reflected wave superimposes on the original wave; causes cellular damage of blood vessels *Will not happen if keep the sound head moving.

Answer 16

Standing wave

Question 17

the alternating current is constant, therefore the stimulus is constant. This allows heat to be built up by the constant friction/vibration of the tissues. Causes thermal effects.

Answer 17

Continuous

Question 18

the alternating current is intermittently interrupted. Less heat built up, therefore creates non-thermal effects. Recommended at 20% duty cycle (or 80% interrupted).

Answer 18

Pulsed

Question 19

describes the physical area on the sound head that transmits the sound waves. *Treatment area should be no bigger than 2 x’s the ERA for the sound head! never 100%

Answer 19

ERA- effective radiating area

Question 20

describes the uniformity of the sound waves being emitted; cannot be 100%, but closer to 1:1 ratio the more consistent the delivery of sound waves will be. Should not exceed 5:1 ratio. *Higher BNR’s require more movement of sound head to avoid developing “hot spots.”

Answer 20

BNR- beam nonuniformity ratio

Question 21

• Increased tissue extensibility- only lasts approx 10 minutes, therefore must stretch with or immediately after
• Decreased muscle spasm
• Increased nerve conductivity
• Increased metabolism
• Increased circulation
• Decreased pain perception

Answer 21

Thermal Effects

Question 22

• Increased histamine release
• Increased phagocytosis
• Increased fibroblasts
• Tissue regeneration
• Wound healing
• Cell membrane alteration- increased permeability from stable cavitation
• Acoustic microstreaming- improved cell membrane structure and function, helps with pain

Answer 22

Nonthermal effects

Question 23

• Soft tissue repair/wound healing
• Resolving pitting edema
• Contractures/adhesions
• Pre-stretch or during stretch
• Chronic inflammation
• Bone healing
• Pain/spasm

Answer 23

Indications

Question 24

• Malignancy
• Pregnancy
• Cardiac dysfunction
• Pacemakers
• Areas of impaired sensation
• Infected areas
• Over eyes/spine/heart/spinal cord/joint cement

Answer 24

Contraindications

Question 25

Use of anti-inflammatory medicine as part of the medium. Sound waves penetrate skin and take medicine ions with them. *Medicine becomes systemic! Caution must be taken to not over-dose a patient who is already taking steroid anti-inflammatory medicines.

Answer 25

Phonophoresis

Question 26

PULSED

Answer 26

Duty cycle (Phonophoresis)

Question 27

LOW

Answer 27

Intensity (Phonophoresis)