Bioeffects Flashcards
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 calorimeter
b. a thermocouple
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
c. thermocouple, calorimeter
True or False?
The biological effects of ultrasound are thought to be negligible and thus, few investigations have been performed on the subject.
False
True or False?
It is generally believed that the effects of ultrasound on biologic media are minimal.
False
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
d. when the benefits outweigh the risks
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. observable in a living body
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
c. discernible in a test tube
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
d. the transducer
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.
False
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.
True
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.
True
True or False?
A bioeffect identified through the mechanistic approach rather than the empirical approach is more likely to have clinical significance.
False
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.
True
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. cause-effect
Which of these terms best describes the empirical investigation of bioeffects?
a. cause-effect
b. exposure-response
c. cause-response
d. exposure-cure
b. exposure-response
When studying bioeffects, which research approach is more important?
a. empirical
b. mechanistic
c. neither is important
d. both are equally important
d. both are equally important
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
c. duration of the study
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
b. fractionation
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
c. unfocused
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
d. 41 degrees C
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
c. can be lethal to living things
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
b. stable cavitation relates to oscillating bubbles while transient relates to bursting bubbles
Which of the following is related to cavitation bioeffects?
a. TIS
b. MI
c. cavitation index
d. pulsatility index
b. MI
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
c. low frequency, high pressure
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
c. 6 MHz, 2 MPa
What is epidemiology the study of?
a. large groups
b. the prevalence of disease
c. acoustic bioeffects on the fetus
d. in vitro effects
b. the prevalence of disease
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
d. none of the above
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
b. prospective and randomized
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
b. 100 mW/cm^2
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
d. 1 W/cm^2
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.
True
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.
True
True or False?
It is generally believed that the ultrasound bioeffects are minimal at intensity levels typical of those produced by diagnostic imaging equipment.
True
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
c. ultrasound is considered highly toxic
