Physics Principles 15% Pt 2 Flashcards
How is density related to impedance?
HIGHER DENSITY = _______ IMPEDANCE
Higher impedance!
Axial resolution equation= 1/2 ()
Axial resolution = 1/2 (SPL)
What media has the highest propagation speed?
BONE= highest propagation speed
Increasing the transducer frequency on a multi hertz, transducer will improve _____ resolution in the near and far Field
Axial resolution
Decreasing the number of cycles in a pulse will improve what resolution? (Short pulses)
Axial resolution
Which of the following imaging parameters (resolution) is responsible for the ability to resolve to separate cysts that are side-by-side in the liver?
Lateral resolution
________ resolution is the minimum reflector separation required to produce separate echoes
Spatial resolution
DB= _____ of two sound intensity
Ratio
What phenomenon is described as the conversion of pressure waves into an electrical voltage?
Piezoelectric effect
Cycles are added to a pulse, which of the following types of resolution is degraded?
Axial
Increasing the PRF improves _______ resolution
PRF 👍😊= temporal 👍
There is a 100% reflection on the beam strikes in interphase at _______ angle
Critical angle= 100% reflection
Frequency could be detected by the human ear? ______Hz
2000 Hz
Which type of image resolution is negatively affected by the placement of multiple focal zones at the area of interest?
Temporal
Preferred levels of axial and lateral resolution will demonstrate/ _____ numerical value
Low
60% transmission, what percent is reflected to the transducer? (Incident equation)
Incident beam (100%) equals reflected beam plus transmitted beam
40
Transmit delay/receive focusing improves ______ resolution
LATERAL RESOLUTION hey
Increasing line density increases
Spatial resolution
Specular reflection of the greatest ________, ______, _______
Amplitude, intensity, frequency
Amplitude, doubles, intensity :
Increases by 4!
Impedance is defined as the _____ of particle pressure to particle velocity at a given point
Ratio
What system Parimeter is defined as the ability to differentiate to separate objects on the image?
Resolution
TGC necessary due to?
Attenuation, scatter, reflection
If the reflector dimensions are less than the wave length of the pulse what occurs?
RAYLEIGH SCATTERING
Speed of sound is primarily, depending on the______ in which the sound travels
SPEED= median
How do you determine the lateral resolution for unfocused, single element transducer?
1/2 element diameter
During refraction, angle of transmission increases, meaning speed ______ than before
Speed
Increasing scanline density leads to improved _______ resolution
SPATIAL
Reflection
The greater the difference in ______ rate of the two media, the greater amount of reflection
Attenuation rate
Amplitude increases by 1/2, intensity, decreases by
amplitude = 1/2
Intensity= 1/4
Angle at which total reflection occurs is called the
Critical angle
Diffuse reflection= occurs when the beam strikes a ______ rough surface
Large Rough
Put an order from lowest to highest according to their impedance
Air, blood, bones, liver
Lowest equals air
Blood
Liver
Bone
If the incident beam angle is 25°, what is the angle of reflection?
25
The sonographer can improve AXIAL resolution by _____ frequency, transducer
Higher frequency transducer
When the beam is absorbed by the medium, energy is lost in the form of
Heat
As the sound travels through soft tissue, what happens to the period of the wave?
Remains constant 
Lateral resolution is best at what location in the beam?
Focal zone
As the frequency of a wave, doubles, the wave length
Halved
Curved PE elements and acoustic lenses will improve which two types of resolution?
Elevation and lateral
Huygen’s principle : describes the formation of the sound being by ______ sound source along the path of the beam
MULTIPLE
Which of the pulse is produced from a 7MHz transducer would have the best lateral and axial resolution?
2mm diameter = lateral
3 pulses= axial
M-mode = HIGHEST _______ resolution
M-mode= TEMPORAL
Reflection = ________
Rhymes
Redirection
Spatial pulse length= 4mm
Axial resolution?
1/2 (4)= 2
You are scanning the transducer that maintains a 2 scan lines per sector degree. Changes 45 to 90° sector angle.
Degrades ______ resolution
More scan lines = worse
Temporal resolution
