Physics 1 Test Ch 10, 11 Flashcards
Axial resolution is associated with..
Shorter spatial pulse length Short pulse duration High frequency Fewer cycles per pulse Lower numerical values
Resolution
The ability to accurately distinguish 2 structures laying close together.
Axial resolution is measured in
Distance (mm and cm)
Axial resolution
Measures the ability of a system to display 2 structures that are parallel to the sound beams main axis
Lateral resolution
The ability to identify 2 structures that are perpendicular to the sound beams main axis.
All names for Lateral resolution
Lateral
Angular
Transverse
Azimuthal
Axial resolution is determined by
Pulse length
Lateral resolution is determined by
Beam width
Does axial resolution change.
No
Does lateral resolution change?
Yes. Changes with depth. Best at focus.
Axial resolution is best in near field with….
Shortest pulse
Axial resolution is best in far field with..
Shortest pulse
Lateral resolution is best in near field with…
Smallest diameter crystal
Lateral resolution in far field is best with…
Largest diameter and highest frequency.
Axial resolution is best with…
Shortest pulse
Highest frequency
Fewest cycles
Lateral resolution is best with..
Narrowest beam.
Best at focal point.
External focusing
With a lens
Internal focusing
With a curved active element
Phased array focusing
With electronics of the ultrasound system
Lens focusing is
External
Fixed
Conventional
Mechanical
Curved active element is
Internal
Fixed
Conventional
Mechanical
Electronic focusing is
Phased array
Adjustable
All names for axial resolution
Longitudinal Axial Range Radial Depth
Most common form of fixed focusing is..
Internal focusing
Curvature of PZT is..
Internal focusing
As the curvature of the PZT becomes more pronounced…
The degree of focusing increases.
Phased array means…
Adjustable or multiple focusing.
The 4 effects of focusing
Beam diameter in near field and focal zone are reduced.
Focal depth is shallower.
Beam diameter in far zone increases.
Focal zone is smaller.
Frequency of continuous waves is determined by…
Frequency of electrical signal from the ultrasound system.
Frequency of a pulsed wave is determined by…
Thickness of ceramic and speed of sound in ceramic.
Focal length is determined by…
Diameter of ceramic and frequency of sound.
Beam divergence is determined by…
Diameter of ceramic and frequency of sound.
A-mode
Amplitude
B-mode
Brightness
M-mode
Motion
X axis for a-mode measures…
Reflector depth.
Y axis on a-mode represents
Strength/amplitude.
X axis for b-mode measures
Depth.
X axis measures what for m-mode
Time.
Y axis measures what in m-mode.
Depth.
Z axis measures what in b-mode.
Amplitude.
What does y-axis measure in b-mode?
Nothing.