Chapters 8/9 Flashcards
Which of the following is not assessed with a tissue-equivalent (TE) phantom?
beam width
Tissue-equivalent phantoms are filled with a substance containing
graphite
Which of the following pulsed imaging techniques demonstrates the highest acoustic output?
Pulsed doppler
Test objects evaluate
detail resolution and beam resolution
A hydrophone is used in the following form
- a small transducer element mounted on the end of a hollow needle
-a large piezoelectric membrane with small electrodes on both sides
Which of the following pulsed-wave techniques demonstrates the lowest sonographic output?
gray-scale
Doppler test objects and flow phantoms enable the evaluation of all of the following except
color doppler spatial resolution
Hydrophones are used to measure the acoustic output of various sonographic instruments.
True
Doppler test objects and flow phantoms are not able to evaluate gate location.
False
In soft tissue, a temperature rise is considered significant once it exceeds
1.5 degrees celsius
Which of the following describes cavitation?
bubbles in a liquid medium
No bioeffects have been observed in mammalian tissues that contained well-defined gas bodies at peak rarefactional pressure values (MPa) of less than ______.
0.4
Plant studies are useful primarily for
understanding cavitational effects in living tissue
The extent of temperature rise produced depends on:
intensity and frequency
Which of the following pulsed imaging techniques demonstrates the highest acoustic output?
spectral doppler
No bioeffects have been observed in mammalian tissues at mechanical index values of less than ________.
0.4MPa
Attenuation in soft tissue is due primarily to
Absorption
Which of the following relates to heating?
absorption
A significant increase in the temperature of tissues close to the transducer is a result of ________.
Transducer self heating
Bioeffects have not been observed in experimental animals with focused intensities below
1mW/cm
ALARA
as low as reasonably achievable
How do you ensure ALARA is being used?
-shorten exam time
-lowest output
Which of following cannot be measured or calculated by a hydrophone?
Impedance
Acoustic output is important when considering
bioeffects and patient safety
The American College of Radiology (ACR Ultrasound Accreditation program requires at least ___ testing for instrument quality control
Semiannual
Routine quality control testing is required by the
AIUM
Biological effects have not occurred at temperatures lower than
39 degrees c
Test objects are used by engineers rather than instrument operators.
False. Phantoms and test objects can be used by service personnel and instrument operators
For exposure duration up to 50 hours, there have been no significant adverse biological effects observed from temperature increases less than or equal to 1.5 degrees C.
True
Tissue-equivalent propagation speed in gel? Rubber?
-gel= 1.54mm/us
-rubber=1.45mm/us
Graphite acts as __ within tissue equivalent phantoms?
Scatters
Hydrophones measure
Period, PRP, PD, Frequency, PRF, DF, Amplitude, Wavelength, SPL, Intensity
The echo- free (cystic) regions contained within tissue-equivalent phantoms are of various diameters and evaluate detail resolution.
true
Bio effect is useful in ultrasound.
True
Bio effect occurrence depends on
temperature exposure
Bio effect is decreased using?
ALARA
Tissue-equivalent phantoms are assessed with
-dynamic range
-contrast resolution
-TGC
-penetration
-detail resolution
Doppler test objects and flow phantoms enable the evaluation of
-spectral-display speed calibration
-sample volume location
-penetration of spectral and color doppler instruments
a hydrophone produces a voltage
true
