Ultrasound Flashcards Preview

DPT 623 Physical Agents > Ultrasound > Flashcards

Flashcards in Ultrasound Deck (48)
Loading flashcards...
1

Define Transducer (sound head)

A crystal/part of ultrasound unti that contains crystal that converts electrical energy into sound

2

Define Power

Amount of acoustic energy per unit time. Expressed in Watts (W)

3

Define Intensity

Power per unit area of the sound head. Expressed in Watts/centimeter squared (W/cm2)

4

Define Phonophoresis

Application of ultrasound with a topical drug to facilitate transdermal drug delivery

5

What are some clinical applications of ultrasound?

Soft tissue shortening, pain control, dermal ulcers, surgical skin incisions, tendon injuries, resorption of calcium deposits, bone fractures, carpal tunnel syndrome, phonophoresis, plantar warts, herpes zoster infection

6

List the contraindications for US

Malignant tumor, pregnancy, CNS tissue, joint cement, plastic components, pacemaker, thrombophlebitis, eyes, reproductive organs

7

What the precautions for US?

Acute inflammations, epiphyseal plates, fractures, breast implants

8

Define Absorption

Conversion of the mechanical energy of ultrasound into heat

9

Define Frequenecy

Number of compression-rarefaction cycles per unit of time

10

Pick one:

Increasing the frequency of the US causes a(n) (increase/decrease) in its depth of penetration & concentration of the US energy in the tissue

Decrease

11

Define Duty Cycle

The proportion of the total treatment time that the US is on

12

What is the difference between 20% and 100% duty cycle?

20% duty cycle means the US is on 20% & off 80% for the treatment time

100% duty cycle is continuous & is on the entire treatment time (100%)

13

Ultrasound

Sound with a frequency greater than 20,000 cycles per second that, when applied to the body, has thermal and non thermal effects. (pg 201)

14

Pulsed ultrasound

Produced only non-thermal effects, has been shown to facilitate tissue healing, modify inflammation and enhance transdermal drug deliver (pg177)

15

Acoustic streaming

A non-thermal effect of ultrasound. The stead, circular flow of cellular fluids induced by ultrasound. This flow is larger in scale than with micro streaming and is thought to alter cellular activity by transporting material from one part of the ultrasound field to another. (pg178 & 199)

16

Microstreaming

A non-thermal effect of ultrasound. Microscope eddying (circular movement of water counter to that of the main current) that takes place near any small, vibrating object. Micro streaming occurs around the gas bubbles set into oscillation by cavitation.

17

Cavitation

A non-thermal effect of ultrasound. The formation, growth and pulsation of gas-filled bubbles caused by ultrasound. During the compression phase of an US wave, bubbles present in the tissue are made smaller, and during the rarefaction phase, they expand. Cavitation may be stable or unstable.

18

List some types of tissues that are heated by ultrasound?

Tendons, Ligaments, Joint Capsule, and Fasciae.

19

Therapeutic ultrasound has a frequency of?

Between 0.7 and 3.3 megahertz (MHz)

20

What is the depth in the soft tissue at which ultrasound is absorbed at?

2 to 5 cm

21

True or False? Ultrasound generally heats smaller, deeper areas than superficial heating agents.

True

22

What is considered the best frequency for heating tissues?

1 MHz

23

During an ultrasound what helps keep hot spots from forming?

Continuous movement of the sound head throughout application.

24

What was the first large scale application or ultrasound?

Sound navigation during World War II

25

The types of tissue heated by ultra sound have a high content of what?

Collagen

26

What are the two types of ultrasound used clinically?

Pulsed Ultrasound
Continuous Ultrasound

27

Attenuation is the combination of what three things?

Absorption, Reflection, and Refraction.

28

True or False? The effect of ultrasound on the healing of surgical skin incisions has been demonstrated to be beneficial?

True

29

It is recommended that ultrasound be applied in a pulse mode at a low or high intensity during the acute phase of tendon inflammation?

low

30

True or False? The use of low-dose ultrasound to accelerate fracture healing is now recommended?

True