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Ultrasound Physics Review > Bioeffects > Flashcards

Bioeffects Flashcards

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1
Q

Which two of the following devices convert ultrasound energy into heat?

a. a calorimeter
b. a thermocouple
c. a hydrophone
d. a Schlieren

A

a. a calorimeter

b. a thermocouple

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2
Q

The _____ measures beam intensity at specific locations, whereas a ______ measures the entire energy in a sound beam.

a. calorimeter, thermocouple
b. Schlieren, thermocouple
c. thermocouple, calorimeter
d. thermometer, hydrometer

A

c. thermocouple, calorimeter

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3
Q

True or False?

The biological effects of ultrasound are thought to be negligible and thus, few investigations have been performed on the subject.

A

False

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4
Q

True or False?

It is generally believed that the effects of ultrasound on biologic media are minimal.

A

False

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5
Q

Under which condition is it permissible to perform a diagnostic ultrasound exam?

a. when the patient will benefit
b. when the patient has insurance
c. when the exam is perfectly safe
d. when the benefits outweigh the risks

A

d. when the benefits outweigh the risks

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6
Q

Some ultrasonic bioeffects studies are performed in vivo. what is the meaning of the term in vivo?

a. observable in a living body
b. observations based on an experiment
c. discernible in a test tube
d. estimated in a computer simulation

A

a. observable in a living body

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7
Q

Certain studies of bioeffects are performed in vitro. What is the meaning of in vitro?

a. visible in a living organism
b. observations based on experiments
c. discernible in a test tube
d. perceptible in a living human being

A

c. discernible in a test tube

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8
Q

Which component of an ultrasound system exposes a patient to greatest risk?

a. the CRT
b. the electric cord
c. the pulser
d. the transducer

A

d. the transducer

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9
Q

True or False?

The AIUM suggests that in vitro research confirming bioeffects is valuable and valid. Their results are significant and should be directly applied to the clinical arena.

A

False

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10
Q

True or False?

The mechanistic approach to the study of bioeffects and safety includes the identification of a theoretical construct that could produce an effect.

A

True

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11
Q

True or False?

The empirical approach to the study of bioeffects and ultrasonic safety surveys data involves finding a relationship between exposure and toxic effects.

A

True

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12
Q

True or False?

A bioeffect identified through the mechanistic approach rather than the empirical approach is more likely to have clinical significance.

A

False

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13
Q

True or False?

The AIUM considers an ultrasound-induced biologic tissue temperature rise of less than 2 degrees Centigrade above normal body temperature as safe for clinical studies.

A

True

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14
Q

Which of the following terms best describes the mechanistic investigation of bioeffects?

a. cause-effect
b. exposure-response
c. cause-response
d. exposure-cure

A

a. cause-effect

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15
Q

Which of these terms best describes the empirical investigation of bioeffects?

a. cause-effect
b. exposure-response
c. cause-response
d. exposure-cure

A

b. exposure-response

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16
Q

When studying bioeffects, which research approach is more important?

a. empirical
b. mechanistic
c. neither is important
d. both are equally important

A

d. both are equally important

17
Q

Of the following choices, which is considered the most important for the sonographer with regard to bioeffects?

a. pulse repetition frequency
b. frequency
c. duration of the study
d. imaging mode

A

c. duration of the study

18
Q

Which of the following is not a potential mechanism for production of bioeffects from ultrasound exposure to the body?

a. temperature elevation
b. fractionation
c. cavitation
d. vibration

A

b. fractionation

19
Q

Which of the following ultrasound beams has a characteristic that is most likely to cause temperature elevation in tissue?

a. strongly focused
b. medium focused
c. unfocused

A

c. unfocused

20
Q

According to the AIUM, at what in situ tissue temperature is there danger to a fetus?

a. 100 degrees C
b. 98.6 degrees F
c. 1 degree F over normal temperature
d. 41 degrees C

A

d. 41 degrees C

21
Q

Research has indicated that cavitation _____.

a. never occurs
b. cannot occur with long pulses
c. can be lethal to living things
d. effects are purely theoretical

A

c. can be lethal to living things

22
Q

Which of the following statements regarding cavitation is true?

a. it has never been observed in any biological media
b. stable cavitation relates to oscillating bubbles while transient relates to bursting bubbles
c. it is a nonlethal bioeffect produced in an animal experiments
d. waves with peak pressures less than 100 MPa can never induce cavitation

A

b. stable cavitation relates to oscillating bubbles while transient relates to bursting bubbles

23
Q

Which of the following is related to cavitation bioeffects?

a. TIS
b. MI
c. cavitation index
d. pulsatility index

A

b. MI

24
Q

Which selection has the highest mechanical index?

a. high frequency, high power
b. high PRF, high intensity
c. low frequency, high pressure
d. high spatial pulse length, high PRF

A

c. low frequency, high pressure

25
Q

Which sound wave is least likely to create cavitation?

a. 5 MHz, 2 MPa
b. 2 MHz, 4 MPa
c. 6 MHz, 2 MPa
d. 2 MHz, 2 MPa

A

c. 6 MHz, 2 MPa

26
Q

What is epidemiology the study of?

a. large groups
b. the prevalence of disease
c. acoustic bioeffects on the fetus
d. in vitro effects

A

b. the prevalence of disease

27
Q

Epidemiologic studies of in utero exposure to ultrasound have included all of the following findings except _____.

a. birth weight
b. cancer
c. structural abnormalities
d. none of the above

A

d. none of the above

28
Q

Which of the following epidemiological studies is considered most likely to produce meaningful results?

a. retrospective and prospective
b. prospective and randomized
c. retrospective and empirical
d. prospective and mechanistic

A

b. prospective and randomized

29
Q

What is the highest SPTA intensity of an unfocused ultrasound wave where there have been no observed bioeffects?

a. 1 mW/cm^2
b. 100 mW/cm^2
c. 1000 mW/cm^2
d. 1 W/cm^2

A

b. 100 mW/cm^2

30
Q

The upper limit for the SPTA of a focused ultrasound wave where there have been no observed bioeffects is ______.

a. 1 mW/cm^2
b. 10 mW/cm^2
c. 100 mW/cm^2
d. 1 W/cm^2

A

d. 1 W/cm^2

31
Q

True or False?

One reason focused ultrasound beams with low intensities are less likely to cause bioeffects is that a focused beam is less efficient in heating a large mass of tissue to a critical temperature.

A

True

32
Q

True or False?

Focused sound beams are considered less likely to create bioeffects because the beams will strike fewer gas bubbles that could potentially cavitate.

A

True

33
Q

True or False?

It is generally believed that the ultrasound bioeffects are minimal at intensity levels typical of those produced by diagnostic imaging equipment.

A

True

34
Q

A comprehensive and scholarly review of bioeffects is performed by the American Institute of Ultrasound in Medicine for all of the following reasons except:

a. ultrasound is a versatile technique
b. ultrasound has proven widespread clinical utility
c. ultrasound is considered highly toxic
d. applications of ultrasound are growing considerably

A

c. ultrasound is considered highly toxic

Ultrasound Physics Review (30 decks)

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