Ultrasound Physics: TEST 1 REVIEW
This Ultrasound Physics Test 1 typically covers fundamental sound wave principles,, propagation
speeds, transducer basics, and acoustic interactions with tissue, focusing on frequency,
attenuation, impedance, and decibels. Key concepts involve mechanical/longitudinal waves,
the Doppler effect, and the distinction between ultrasound and audible sound.
4Key Topics for Test 1 Review Sound Basics:
Ultrasound is a mechanical, longitudinal wave (\(>20\text{kHz}\)). Key properties include frequency,
period, wavelength, propagation speed, intensity, power, and amplitude.Wave Interactions
(Attenuation): Sound weakens as it propagates, influenced by path length and frequency.
Processes include reflection, scattering, and absorption. Higher frequencies cause higher
attenuation. Acoustic Impedance: Defined as the product of the density of the medium
(\(kg/m^{3}\)) and the propagation speed of sound through that medium
(\(m/s\)).Reflection & Transmission: Determines how much of the ultrasound wave reflects
back (reflection) or continues (transmission). No reflection occurs if two media have
identical impedances. Definitions & Measurements: Intensity:
\(I=\frac{Power}{Area}\).Temporal Intensities (Largest to Smallest):
\(I_{tp},I_{max},I_{pa},I_{ita}\).Attenuation Coefficient: \(dB\) loss.Wave Behavior: Sound
requires a medium to propagate.Types of Imaging: Understanding basic grayscale imaging
and the role of the transducer.
Quiz_________________?
4 def: intensity, propagation speed, amplitude, which one is determined by medium only? -
Answer✅
SPEED
Quiz_________________?
4 diff types of attenuation -
1
, Answer✅
3 components:
1. Reflection
2. Scattering
3. Absorption
4. Refraction
Quiz_________________?
A. How long does it take a beam of sound to make a trip in 1 cm of soft tissue?
B If it Changes to 1 from skin surface to reflector 20 cm deep, how long does it take that
sound to make a round trip? -
Answer✅
A. 13 microseconds (us)
B. 20 x 13 = 260 microseconds
Quiz_________________?
Acoustic impedence defined as product of? -
Answer✅
Reflection
IMPEDANCE (RAYLS) = DENSITY OF THE MEDIUM (kg/m3)X THE PROP. SPEED OF
SOUND THROUGH THAT MEDIUM (m/s)
Quiz_________________?
Amplitude? -
2
, Answer✅
bigness of a wave
Difference btwn max value and average or undisturbed value, or diff btwn min value and
average value
Units:
1. pressure - pascals
2. density - g/cm3
3. particle motion - cm, inches, any distance
4. descibels (dB)
Determined by: source
Adjustable: Yes
How is amplitude measured? measured from middle to max value
Quiz_________________?
Attenuation occurs how? -
Answer✅
Attenuation - sound waves weaken as they propagate; decrease in intensity, power, and
amplitude as sound travels
Determined by 2 factors:
1. Path length
2. Frequency
Distance & Attenuation: Directly related
Frequency & Attenuation: Directly related
3
This Ultrasound Physics Test 1 typically covers fundamental sound wave principles,, propagation
speeds, transducer basics, and acoustic interactions with tissue, focusing on frequency,
attenuation, impedance, and decibels. Key concepts involve mechanical/longitudinal waves,
the Doppler effect, and the distinction between ultrasound and audible sound.
4Key Topics for Test 1 Review Sound Basics:
Ultrasound is a mechanical, longitudinal wave (\(>20\text{kHz}\)). Key properties include frequency,
period, wavelength, propagation speed, intensity, power, and amplitude.Wave Interactions
(Attenuation): Sound weakens as it propagates, influenced by path length and frequency.
Processes include reflection, scattering, and absorption. Higher frequencies cause higher
attenuation. Acoustic Impedance: Defined as the product of the density of the medium
(\(kg/m^{3}\)) and the propagation speed of sound through that medium
(\(m/s\)).Reflection & Transmission: Determines how much of the ultrasound wave reflects
back (reflection) or continues (transmission). No reflection occurs if two media have
identical impedances. Definitions & Measurements: Intensity:
\(I=\frac{Power}{Area}\).Temporal Intensities (Largest to Smallest):
\(I_{tp},I_{max},I_{pa},I_{ita}\).Attenuation Coefficient: \(dB\) loss.Wave Behavior: Sound
requires a medium to propagate.Types of Imaging: Understanding basic grayscale imaging
and the role of the transducer.
Quiz_________________?
4 def: intensity, propagation speed, amplitude, which one is determined by medium only? -
Answer✅
SPEED
Quiz_________________?
4 diff types of attenuation -
1
, Answer✅
3 components:
1. Reflection
2. Scattering
3. Absorption
4. Refraction
Quiz_________________?
A. How long does it take a beam of sound to make a trip in 1 cm of soft tissue?
B If it Changes to 1 from skin surface to reflector 20 cm deep, how long does it take that
sound to make a round trip? -
Answer✅
A. 13 microseconds (us)
B. 20 x 13 = 260 microseconds
Quiz_________________?
Acoustic impedence defined as product of? -
Answer✅
Reflection
IMPEDANCE (RAYLS) = DENSITY OF THE MEDIUM (kg/m3)X THE PROP. SPEED OF
SOUND THROUGH THAT MEDIUM (m/s)
Quiz_________________?
Amplitude? -
2
, Answer✅
bigness of a wave
Difference btwn max value and average or undisturbed value, or diff btwn min value and
average value
Units:
1. pressure - pascals
2. density - g/cm3
3. particle motion - cm, inches, any distance
4. descibels (dB)
Determined by: source
Adjustable: Yes
How is amplitude measured? measured from middle to max value
Quiz_________________?
Attenuation occurs how? -
Answer✅
Attenuation - sound waves weaken as they propagate; decrease in intensity, power, and
amplitude as sound travels
Determined by 2 factors:
1. Path length
2. Frequency
Distance & Attenuation: Directly related
Frequency & Attenuation: Directly related
3
