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2024 VERIFIED ARDMS SPI STUDY GUIDE EXAM WITH CORRECT ANSWERS
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2024 VERIFIED ARDMS SPI STUDY GUIDE EXAM WITH CORRECT ANSWERS
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2024 VERIFIED ARDMS SPI STUDYGUIDE EXAM WITH CORRECT
ANSWERS
Frequency is measured in - CORRECT-ANSWERSHertz (Hz)
is
Cycles per Second
Not affected by sonographer
Increase Frequency; Decrease Depth
In soft tissue, if the frequency of a wave is increased the Propagation Speed
(PS) will... - CORRECT-ANSWERSRemain the Same because stiffness and
density affect Propagation Speed.
What is the audible range? - CORRECT-ANSWERS20-20,000Hz
>20,000Hz=Ultrasound
Which instrument control affects the amplitude (db) of the outgoing signal? -
CORRECT-ANSWERSTransmit Gain;
Amplitude can be affected by the sonographer
What is used to convert Doppler shift information into color? - CORRECT-
ANSWERSAutocorrelation
What is used to process conventional Doppler shift information but is too
slow of a method for Color Doppler? - CORRECT-ANSWERSFast Fourier
transform
Pulse Repetition Frequency - CORRECT-ANSWERSThe number of pulses that
an ultrasound system transmits into the body each second.
Unit: Hz. Typically 4-15 KHz.
PRF and Depth of View are inversely related.
When the system is imaging deeper, the pulse repetition frequency is lower,
as well as, the number of pulses created each second.
,What is the best way to increase the near field length of an ultrasound
beam? - CORRECT-ANSWERSIncrease Transducer Diameter
What is the range of frequencies produced by a dampened PZT element? -
CORRECT-ANSWERSbandwidth
What is bandwidth? - CORRECT-ANSWERSrange of frequencies in a pulse
The percentage of time that the ultrasound instrument is emitting ultrasound
is called? - CORRECT-ANSWERSDuty Factor
The maximum value is 1, the minimum is 0
What is the unit of Duty Factor? - CORRECT-ANSWERSDuty Factor is Unit-less
If the ultrasound is produced as a continuous wave (CW), the duty factor will
have a value of 1. With Pulsed Wave the whole value of On-Time is
fractioned.
What is Q-factor or Quality Factor? - CORRECT-ANSWERSThe "Q factor"
describes the bandwidth of the sound emanating from a transducer
Transducer Q Factor (Q = Quality) is associated with two characteristics of
the crystal
• purity of their sound and
• length of time the sound persists
(Unitless measurement)
Fundamental Frequency(Hz)/Bandwidth(range of frequency in the pulse)
The unit of duty factor is: - CORRECT-ANSWERSUnitless
Clinical imaging transducers are: - CORRECT-ANSWERSWide bandwidth; Low
Q factor
Wide range of frequencies in the pulse and short period of time that the
sound is emitted (pulsed wave)
Power/Area= - CORRECT-ANSWERSIntensity
Increasing wavelength will_______frequency? - CORRECT-ANSWERSDecrease
Beam Properties - CORRECT-ANSWERSThe ultrasound beam propagates as a
longitudinal wave from the transducer surface into the propagation medium,
, and exhibits two distinct beam patterns: - a slightly converging beam out to
a distance specified by the geometry and frequency of the transducer (the
near field), and - a diverging beam beyond that point (the far field).
Does Beam Width directly affect frame rate? - CORRECT-ANSWERSNo:
The following directly affect frame rate:
Depth of Penetration
Field of View
Number of Focuses
and Line Density
What affects frame rate? - CORRECT-ANSWERSDepth of Penetration, Field of
View, Number of Focuses, and Line Density.
Frame Rate= Number of Frames/Second
When will a reflection occur at the boundary of two media? - CORRECT-
ANSWERSIf the acoustic impedances of the tow media are different.
Snell's Law - CORRECT-ANSWERSDescribes the relationship between the
angles and the velocities of the waves.
When an ultrasonic wave passes through an interface between two materials
at an oblique angle, and the materials have different indices of refraction,
both reflected and refracted waves are produced
In ultrasound, Snell's Law
is a formula used to describe the relationship between the angles of
incidence and refraction, when referring to light or other waves passing
through a boundary between two different isotropic media.
The ratio of the sine of the angle of incidence to the sine of the angle of
refraction is a constant, for a given frequency.
The Angle of Incidence - CORRECT-ANSWERSRefers to the angle of deviation
from a perpendicular line to the surface of the tissue
Therefore, the desired orthogonal(perpendicular) incident wave in ultrasound
should be considered to have an angle of incidence of zero.
When the angle of incidence is greater, fewer sound waves are reflected
back to the transducer resulting in a more hypoechoic (darker) image with
less clarity.
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