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DPT 623 Physical Agents > Ultrasound > Flashcards

Ultrasound Flashcards

1
Q

Define Transducer (sound head)

A

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

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2
Q

Define Power

A

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

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3
Q

Define Intensity

A

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

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4
Q

Define Phonophoresis

A

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

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5
Q

What are some clinical applications of ultrasound?

A

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

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6
Q

List the contraindications for US

A

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

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7
Q

What the precautions for US?

A

Acute inflammations, epiphyseal plates, fractures, breast implants

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8
Q

Define Absorption

A

Conversion of the mechanical energy of ultrasound into heat

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9
Q

Define Frequenecy

A

Number of compression-rarefaction cycles per unit of time

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10
Q

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

A

Decrease

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11
Q

Define Duty Cycle

A

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

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12
Q

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

A

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%)

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13
Q

Ultrasound

A

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)

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14
Q

Pulsed ultrasound

A

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

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15
Q

Acoustic streaming

A

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)

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16
Q

Microstreaming

A

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.

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17
Q

Cavitation

A

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.

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18
Q

List some types of tissues that are heated by ultrasound?

A

Tendons, Ligaments, Joint Capsule, and Fasciae.

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19
Q

Therapeutic ultrasound has a frequency of?

A

Between 0.7 and 3.3 megahertz (MHz)

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20
Q

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

A

2 to 5 cm

21
Q

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

A

True

22
Q

What is considered the best frequency for heating tissues?

A

1 MHz

23
Q

During an ultrasound what helps keep hot spots from forming?

A

Continuous movement of the sound head throughout application.

24
Q

What was the first large scale application or ultrasound?

A

Sound navigation during World War II

25
Q

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

A

Collagen

26
Q

What are the two types of ultrasound used clinically?

A

Pulsed Ultrasound

Continuous Ultrasound

27
Q

Attenuation is the combination of what three things?

A

Absorption, Reflection, and Refraction.

28
Q

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

A

True

29
Q

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

A

low

30
Q

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

A

True

31
Q

If you were to use low-dose ultrasound to accelerate fracture healing, how long would u apply it?

A

15-20 minutes daily

32
Q

Transcutaneous drug delivery provides a higher initial drug concentration at the delivery site, avoids gastric irritation, and ?

A

Avoids first-pass metabolism by the liver

33
Q

Transcutaneous drug delivery avoids?

A

pain, trauma, and infection risk associated with injection and allows delivery to a larger area than is readily achieved by injection

34
Q

The superficial layer of skin that acts as a protective barrier, preventing foreign materials from entering the body through the skin is known as what?

A

stratum corneum

35
Q

Rehabilitation practitioners primarily use phonophoresis to deliver the corticosteroid anti-inflammatory medication dexamethasone through the skin for treatment of?

A

tendinitis and tenosynovitis

36
Q

If a patient with rheumatoid arthritis or asthma is taking corticosteroids by mouth, should hydrocortisone or dexamethasone be given by phonophoreis?

A

No, because it would increase the risk for adverse effects.

37
Q

True or false? Ultrasound can be applied to breast implants?

A

False, heat may increase the pressure inside a breast implant and cause it to rupture

38
Q

At what temperature do malignant tumors decrease in size while healthy tissue is left undamaged?

A

42-43 Degrees Celsius or 108-109 Degrees Fahrenheit.

39
Q

Why can Ultrasound be applied over some prosthetic’s but not others?

A

Methylmethacrylate cement and plastic are used in fixation or as components in the actual prosthetic limbs. Metal fixtures have not been shown to rapidly heat with Ultrasound techniques.

40
Q

True or False: According to Lehmann, it is safe to apply Ultrasound at the site of epiphyseal plates.

A

True. Lehmann states that Ultrasound can be applied over epiphyseal plates as long as no pain is noted.

41
Q

What dose of Ultrasound has been shown to accelerate fracture healing?

A

Low doses of Ultrasound has been shown to accelerate fracture healing.

42
Q

What can Ultrasound standing waves cause?

A

Ultrasound standing waves can cause blood cell stasis because of collections of gas bubbles and plasma at anti-nodes and collections of cells at nodes.

43
Q

There are two main sources where possible cross-contamination from the Ultrasound can occur, what are they?

A

The transducer head and transmission gel are the most common sites where bacteria and other potential pathogenic organisms are found.

44
Q

What duty cycle is selected when the goal is to increase the temperature of the tissue where the Ultrasound is being applied?

A

100% (Continuous) Duty Cycle

45
Q

What duty cycle is selected when the goal is to use Ultrasound without the thermal effects being applied?

A

20% (Pulsed) Duty Cycle

46
Q

Define Rarefaction.

A

Rarefaction is the decrease in density of a material as Ultrasound waves pass through it.

47
Q

Define Compression.

A

Compression is the increase in density of a material as Ultrasound waves pass through it.

48
Q

How do you prevent standing waves during Ultrasound treatment?

A

Sound waves are created when the sound head is not being moved during the treatment period.

DPT 623 Physical Agents (16 decks)

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