ARDMS SPI Study Guide (Ultrasound Physics
Certification Test Study Questions) Correct Q-Bank
Quizzes & Answers, 2025/2026
In soft tissue, if the frequency of a wave is increased the Propagation Speed (PS)
will... - (ANSWER)Remain the Same because stiffness and density affect
Propagation Speed.
What is the audible range? - (ANSWER)20-20,000Hz
>20,000Hz=Ultrasound
Frequency is measured in - (ANSWER)Hertz (Hz)
is
Cycles per Second
Not affected by sonographer
Increase Frequency; Decrease Depth
A period is the length of time it takes for - (ANSWER)one complete wavelength to
pass a fixed point
PRP is determined by - (ANSWER)Transmit time and receive time.
,Period is measured in - (ANSWER)Time (μs)
When the sonographer changes the imaging depth what parameters are
changed? - (ANSWER)PRP, PRF, Duty Factor
What is duty factor? - (ANSWER)The percentage or fraction of time that the
system is transmitting a pulse (Time Sound is ON or ON-Time).
Propagation Speed in SOFT TISSUE - (ANSWER)1.54 mm/μs
(1540 m/sec)
Unit of measurement for Pulse Duration, Duty Factor, PRP, and Period -
(ANSWER)Time, (μs)
Pulse duration is determined by - (ANSWER)Sound Source Only
Pulse Duration is controlled by - (ANSWER)the ultrasound system and transducer
Pulse Duration Formula - (ANSWER)pulse duration (μs) = # cycles in
pulse/frequency(MHz)
PD= Number of cycles in Pulse/ Frequency(Hz)
, Spatial Pulse Length (SPL) (measurement) - (ANSWER)The distance that a pulse
occupies in space from the start to the end of a pulse.
(mm)
Typical values for spatial pulse length in soft tissue. - (ANSWER)0.1 to 1.0 mm
Spatial pulse length is determined by - (ANSWER)sound source and medium
Spatial Pulse Length is directly proportional to - (ANSWER)the Number of Cycles
in the Pulse
and
the Wavelength
(Directly Proportional means that increased SPL will increase both the number of
cycles in the pulse and the wavelength if increased).
Spatial pulse length is inversely proportional to - (ANSWER)Frequency (MHz)
(Inversely Proportional means that increased SPL will lower frequency. This is
because axial resolution is better with lower frequency)
Certification Test Study Questions) Correct Q-Bank
Quizzes & Answers, 2025/2026
In soft tissue, if the frequency of a wave is increased the Propagation Speed (PS)
will... - (ANSWER)Remain the Same because stiffness and density affect
Propagation Speed.
What is the audible range? - (ANSWER)20-20,000Hz
>20,000Hz=Ultrasound
Frequency is measured in - (ANSWER)Hertz (Hz)
is
Cycles per Second
Not affected by sonographer
Increase Frequency; Decrease Depth
A period is the length of time it takes for - (ANSWER)one complete wavelength to
pass a fixed point
PRP is determined by - (ANSWER)Transmit time and receive time.
,Period is measured in - (ANSWER)Time (μs)
When the sonographer changes the imaging depth what parameters are
changed? - (ANSWER)PRP, PRF, Duty Factor
What is duty factor? - (ANSWER)The percentage or fraction of time that the
system is transmitting a pulse (Time Sound is ON or ON-Time).
Propagation Speed in SOFT TISSUE - (ANSWER)1.54 mm/μs
(1540 m/sec)
Unit of measurement for Pulse Duration, Duty Factor, PRP, and Period -
(ANSWER)Time, (μs)
Pulse duration is determined by - (ANSWER)Sound Source Only
Pulse Duration is controlled by - (ANSWER)the ultrasound system and transducer
Pulse Duration Formula - (ANSWER)pulse duration (μs) = # cycles in
pulse/frequency(MHz)
PD= Number of cycles in Pulse/ Frequency(Hz)
, Spatial Pulse Length (SPL) (measurement) - (ANSWER)The distance that a pulse
occupies in space from the start to the end of a pulse.
(mm)
Typical values for spatial pulse length in soft tissue. - (ANSWER)0.1 to 1.0 mm
Spatial pulse length is determined by - (ANSWER)sound source and medium
Spatial Pulse Length is directly proportional to - (ANSWER)the Number of Cycles
in the Pulse
and
the Wavelength
(Directly Proportional means that increased SPL will increase both the number of
cycles in the pulse and the wavelength if increased).
Spatial pulse length is inversely proportional to - (ANSWER)Frequency (MHz)
(Inversely Proportional means that increased SPL will lower frequency. This is
because axial resolution is better with lower frequency)
