DMS 101 TEST 2 QUESTIONS AND ANSWERS
What does the backing layer do? - Answers :-Dampen Pulse
-Shorten pulse duration
-limits ringing of pulse
Between spatial pulse length, pulse duration, bandwidth and axial resolution, which one
increases with pulse damping? - Answers :Bandwidth
Operating frequency equation - Answers :Operating frequency equals propagation
speed in PZT material divided by 2 X the thickness of the PZT material
What happens to the operating frequency when the thickness of the PZT is decreased?
- Answers :It increases
Axial resolution equation - Answers :SPL divided by 2
Which produces a higher frequency, thinner or thicker elements? - Answers :Thinner
elements
Electricity --> transducer --> sound is an example of? - Answers :Indirect PZT effect
Focal length AKA - Answers :Near Zone Length
What is an example of an annular array transducer? - Answers :Transvaginal
transducer
Lateral resolution equals ? - Answers :Beam diameter
The only way the sonographer can change the axial resolution is to use a transducer
with what? - Answers :A higher frequency
Can there be more than one matching layer? - Answers :Yes
Matching layer helps increase what? - Answers :The amount of sound that is
transmitted into the tissue
Where is the matching layer found and why? - Answers :Where: in front of the crystals.
Why: it has an intermediate impedance in relation to crystal and tissue
Explain electronic focus (curvature) - Answers :Electronic curvature is related to a firing
pattern which focuses an US beam
With a linear phased array, what is the firing pattern that focuses a sound beam? -
Answers :Electronic curvature
, What kind of "lobe" do mechanical transducers make? What about phased array? -
Answers :Mechanical: side lobe
Phased array: grating lobe
Steering beam is also called: - Answers :Electronic slope
[regarding mechanical transducer] If there are 100 scan lines, how many pulses are
there? - Answers :100 pulses
Natural PZT materials - Answers :Amber, Rochelle salt, tourmaline, quartz
Slice thickness resolution AKAs: - Answers :Elevational resolution
Out of plane focusing
Z axis
Slice thickness
Section thickness
Elevational axis
Does ultrasound use narrow or broad bandwidth? - Answers :Broad bandwidth
What does beam diameter affect most? - Answers :Lateral resolution
If we use more scan lines or more focal zones, which resolution gets reduced? -
Answers :Temporal resolution. All other resolutions increase.
If the diameter of a transducer is increased, the far field beam width will be? - Answers
:Reduced
The ability to distinguish structures perpendicular to the beam path is what? - Answers
:Lateral resolution
What does LATA stand for? - Answers :Lateral
Angular
Transverse
Azimuthal
What does LARRD stand for? - Answers :Longitudinal
Axial
Range
Radial
Depth
What type of transducer is most commonly associated with grating lobes? - Answers
:Phased array
The ideal matching layer is? - Answers :1/4 wavelength
What does the backing layer do? - Answers :-Dampen Pulse
-Shorten pulse duration
-limits ringing of pulse
Between spatial pulse length, pulse duration, bandwidth and axial resolution, which one
increases with pulse damping? - Answers :Bandwidth
Operating frequency equation - Answers :Operating frequency equals propagation
speed in PZT material divided by 2 X the thickness of the PZT material
What happens to the operating frequency when the thickness of the PZT is decreased?
- Answers :It increases
Axial resolution equation - Answers :SPL divided by 2
Which produces a higher frequency, thinner or thicker elements? - Answers :Thinner
elements
Electricity --> transducer --> sound is an example of? - Answers :Indirect PZT effect
Focal length AKA - Answers :Near Zone Length
What is an example of an annular array transducer? - Answers :Transvaginal
transducer
Lateral resolution equals ? - Answers :Beam diameter
The only way the sonographer can change the axial resolution is to use a transducer
with what? - Answers :A higher frequency
Can there be more than one matching layer? - Answers :Yes
Matching layer helps increase what? - Answers :The amount of sound that is
transmitted into the tissue
Where is the matching layer found and why? - Answers :Where: in front of the crystals.
Why: it has an intermediate impedance in relation to crystal and tissue
Explain electronic focus (curvature) - Answers :Electronic curvature is related to a firing
pattern which focuses an US beam
With a linear phased array, what is the firing pattern that focuses a sound beam? -
Answers :Electronic curvature
, What kind of "lobe" do mechanical transducers make? What about phased array? -
Answers :Mechanical: side lobe
Phased array: grating lobe
Steering beam is also called: - Answers :Electronic slope
[regarding mechanical transducer] If there are 100 scan lines, how many pulses are
there? - Answers :100 pulses
Natural PZT materials - Answers :Amber, Rochelle salt, tourmaline, quartz
Slice thickness resolution AKAs: - Answers :Elevational resolution
Out of plane focusing
Z axis
Slice thickness
Section thickness
Elevational axis
Does ultrasound use narrow or broad bandwidth? - Answers :Broad bandwidth
What does beam diameter affect most? - Answers :Lateral resolution
If we use more scan lines or more focal zones, which resolution gets reduced? -
Answers :Temporal resolution. All other resolutions increase.
If the diameter of a transducer is increased, the far field beam width will be? - Answers
:Reduced
The ability to distinguish structures perpendicular to the beam path is what? - Answers
:Lateral resolution
What does LATA stand for? - Answers :Lateral
Angular
Transverse
Azimuthal
What does LARRD stand for? - Answers :Longitudinal
Axial
Range
Radial
Depth
What type of transducer is most commonly associated with grating lobes? - Answers
:Phased array
The ideal matching layer is? - Answers :1/4 wavelength
